There are lots of ways to express a consequence in either the same sentence as its cause or a new one
THE NEED TO GIVE CAUSES ALONG WITH CONSEQUENCES
In one sense, every event or state is a consequence, since they all have a cause. What “expressing consequences” really means is linking specific consequences to specific causes, or highlighting the consequential nature of an event or state. To do this, we usually need to mention the cause as well.
Consequences are not unique in needing to appear alongside a second meaning like cause. Other kinds of information with this need are examples (alongside the naming of a general class – see 1. Simple Example-Giving), comparisons (alongside a mention of something similar or opposite – see 149. Saying How Things are Similar), and precise identifications (alongside vaguer general equivalents – see 117. Saying More Precisely What is Meant).
As with all of these other areas, the two related meanings can be expressed together in a single sentence or separately in different ones. I want to consider here the variety of language that is possible with consequences expressed in each of these two basic ways, and to highlight some common grammar problems that arise.
Consequences named in a different sentence from their cause normally follow it. There are two main types. The first is anticipated by a word in the first sentence meaning “consequence”, like this:
(a) The popularity of sugar has a visible consequence. More people are overweight.
The second sentence here identifies the consequence whose existence has been established in the first. It is a kind of sentence that is examined more fully in the Guinlist post 117. Saying More Precisely what is Meant. The other main type of consequence-naming new sentence is not anticipated by a word in the previous sentence. Instead it is recognisable just from its saying something that can only be interpreted as a consequence, like this:
(b) South America was colonised mostly by Spain. Spanish is now the main language there.
Consequence is just one of many possible unstated links between two sentences (see 18. Relations Between Sentences). Like most of the others, it can also be made clearer through the addition of link-showing language to the second sentence, most particularly a “logical connector” (see 40. Conjunctions versus Connectors). The main consequence connectors are consequently, in consequence, as a consequence, as a result, therefore, hence, for this reason, that is why and thus. Subtle but important differences between them are discussed in the Guinlist post 20. Problem Connectors.
Various other kinds of word are also usable in the second sentence instead of connectors, such as adjectives like resultant and nouns like consequence (see 112. Synonyms of Connectors). However, these do not include conjunctions, which require a comma to be placed between two linked ideas rather than a full stop (see 30. When to Write a Full Stop). Knowing which words are conjunctions and which are not is often just a matter of memorization.
SAME-SENTENCE CONSEQUENCES (CONJUNCTIONS)
Conjunctions are the most obvious means of giving a consequence alongside its cause in the same sentence. One important group is so, so that and so … that:
(b) The immigrants worked hard so they became rich.
(c) The immigrants worked hard so that they became rich.
(d) The immigrants worked so hard that they became rich.
With regard to these, I would suggest that so by itself emphasises the logical expectedness of the consequence, while the other two simply state that it was a result without suggesting any logical expectedness. The same difference seems to exist between the connectors therefore and as a result (see 20. Problem Connectors) and between the causal conjunctions since and because (see 61. “Since” versus “Because”).
On the other hand, putting the so before the adverb hard in (d) tells us that the hardness of the work was exceptional. This use of so with an adverb or adjective is not to be confused with the use without a partner that (see 156. Mentioning What the Reader Knows Already, #6). It can go with the second verb in the sentence as well as the first (see 88. Exotic Grammar Structures 1), and it can also start the sentence, with the following verb and its subject ordered as in questions (see 64. Double Conjunctions). It becomes such when followed by a noun, with or without an adjective in between (such [hard] work that …).
Other possible consequence conjunctions are with the result that, and (which does not primarily indicate consequence, but often suggests it), and so (used more in speech than writing), plus various combinations of and + connector (and therefore, and hence, and thus, and consequently), which all emphasise the consequentiality (see 40. Conjunctions versus Connectors and 125. Stress and Emphasis).
Of all these possibilities, so that needs a little extra care, since with different surrounding grammar it introduces a purpose instead of a result (see 60. Purpose Sentences with “For”), so that there is a potential for confusing the two uses. The grammar difference can be seen by comparing the following purpose sentence with (c) above:
(e) The immigrants worked hard so that they might become rich.
Here the verb after so that is might become instead of became. It means that the reader cannot any longer tell whether or not the immigrants became rich, only that they wanted to become rich. This meaning of purpose can also be shown by other verbs like might next to the so that verb. In (e) we could use would, and if the earlier verb there was work (present tense) instead of past worked, we would have to use either may or will.
Consequences can additionally be given with conjunctions of cause rather than of result, like this:
(f) Because the immigrants worked hard, they became rich.
We could also use if, suggesting a less definitely-occurring cause (see 118. Problems with Conditional “if”). The start of the sentence seems the best position for a cause conjunction when the consequence is the focus.
Choosing a cause conjunction instead of a consequence one perhaps ensures that the sentence is about only the consequence, rather than about both the cause and the consequence. In other words, the reader will be assumed to know already that the immigrants worked hard, but not that they became rich as a result. For more on because, see 61. “Since” versus “Because” and 72. Causal Prepositions. There is also a use of just because to deny an expected consequence (see 88. Exotic Grammar Structures 1, #2).
SAME-SENTENCE CONSEQUENCES (OTHER POSSIBILITIES)
There are three main other ways to combine a cause and its consequence in the same sentence. The first is by using a verb, like this:
(g) Hard work caused the immigrants to become rich.
The consequence here (the immigrants to become rich) follows the verb caused. Other verbs with a following consequence include ALLOW, ASSIST, BRING ABOUT, COMPEL, CONTRIBUTE TO, ENABLE, ENCOURAGE, ENSURE, FACILITATE, FORCE, HAVE, HELP, IMPEL, INDUCE, LEAD, LEAD TO, LET, MAKE, MAKE … POSSIBLE, MEAN, PERMIT, RESULT IN, STIMULATE and UNDERLIE. One can also use BE with nouns like a cause of or a factor in.
Some other verbs have a consequence before them (as subject) rather than after, for example BE A CONSEQUENCE (or RESULT) OF, REQUIRE and RESULT FROM. You can also use the passive form of many verbs in the first list.
A potential grammar problem with the above verbs is inconsistency in the way the consequence is expressed. Only ALLOW, ASSIST, COMPEL, ENABLE, ENCOURAGE, FORCE, HELP, IMPEL, INDUCE, LEAD, PERMIT and STIMULATE can combine with a to verb in the same way as caused above. Of the others, HAVE, LET and MAKE must drop the to (see 148. Infinitive Verbs without “to” ) while MAKE must also drop BE/BECOME (see 141. Ways of Using MAKE); LEAD TO, RESULT IN, BRING ABOUT and CONTRIBUTE TO are “prepositional” verbs, and hence must be followed either by a noun and -ing verb – the immigrants becoming rich in (g) (see 70. Gerunds) – or by an “action” noun like enrichment (see 131. Uses of “Action” Nouns); FACILITATE, UNDERLIE and MAKE … POSSIBLE also need an -ing verb (often by itself) or action noun, but without a preposition; and ENSURE and MEAN mostly have that before a consequence verb.
Another problem with such a variety of verbs is the subtleties of meaning that they express. Some help in this respect is in the posts 65. Verbs that Mean “Must” or “Can” and 81. Tricky Word Contrasts (2) (#7).
The second main way to combine a cause and consequence in the same sentence is by making the consequence verb a participle with –ing, like this:
(h) The immigrants worked hard, thus becoming rich.
Sentences like this are analysed in more detail in the post 101. Add-On Participles. They often have thus before the -ing verb, though -ing by itself is sufficient. Synonyms of thus are possible too, particularly hence and consequently, but these are rarer than thus in Standard English. Learners who feel that hence is more suitable are likely to be speakers of a particular variety of English, for example that of Kenya and Uganda.
Thirdly, a consequence can be expressed in the same sentence as its cause by means of enough or too plus a following to verb, like this:
(i) The immigrants worked hard enough to become rich.
Too, of course, goes with a negative consequence. If hard enough in (i) is replaced by too hard, the sentence says that the immigrants did not become rich!
Now here is an exercise intended to assist understanding and memorization of some of the points above.
PRACTICE EXERCISE (CONSEQUENCES)
Write one suitable word in each blank space.
1. Some food bacteria produce poisonous substances ………. the result that the food becomes dangerous to eat.
2. Studying grammar books does not always ………. to successful language use.
3. Drug addicts soon run out of money ………. consequently they tend to engage in crime.
4. Adding salt to water lowers its freezing point, ………. making it suitable for controlling ice in winter.
5. People need to know what is in the food they eat. ………. food-labelling is commonplace in supermarkets today.
6. Excessive alcohol consumption can result ………. the liver ………. damaged.
7. Smoking is so ………. to give up ………. increasing its cost has very little effect.
8. The earth’s atmosphere is gradually warming up ………. extreme weather is occurring more frequently.
Answers: 1 = with; 2 = lead or contribute; 3 = and; 4 = thus; 5 = Consequently or Hence or Thus or Therefore or As a result; 6 = in + being; 7 = difficult or hard + that; 8 = so or so that or and.