Some conjunctions can start any sentence, but others start only in special circumstances
DEFINITION OF CONJUNCTIONS
“Do not put a conjunction at the beginning of a sentence” is a rule that many learners of English say they were given at school. The rule, however, is too broad: sometimes you can start a sentence with a conjunction, and sometimes you cannot. I want to try and explain this.
First, there is a need to be clear about what exactly conjunctions are. Most people think of them as “joining words”. This is true, but insufficient, because “joining” can also be done with words that are not conjunctions, especially prepositions and connectors (see 40. Conjunctions versus Connectors and 84. Seven Things to Know About Prepositions). What we must also know is what it is that conjunctions join. The usual answer would probably be “sentences”. This, however, can be misleading, since a sentence with a conjunction is one sentence, not two joined sentences (see 30. When to Write a Full Stop).
The idea that conjunctions “join sentences” probably comes from the most common type of exercise for learning about conjunctions: joining two separate sentences into one. The problem with such an exercise is that it is probably not exactly what real-world writers do when they use a conjunction: they create a single sentence from the beginning, rather than starting with two separate ones.
What conjunctions actually join is verbs. The verbs are joined together in two different ways. Firstly, they are physically joined into the same sentence. If two verbs are used without a conjunction (or any other kind of joining device), they must be in different sentences. If a conjunction is used, the two verbs must be in the same sentence, and any further conjunction that is added must have a further verb with it (there must always be at least one more verb than joining devices in a sentence). If there is only one verb in a sentence, there cannot be any conjunction at all.
To appreciate the physical linking that conjunctions create, consider these conjunction-containing statements:
(a) After one falls asleep, …
(b) One falls asleep and …
If the conjunctions (underlined) were removed, we would be left with complete sentences. However, as they are written, the two sentences are incomplete, and what they lack is a second verb. Any way of completing them correctly has to contain a verb, such as dreams. The only apparent exception to the rule that every conjunction needs its own verb is in some sentences with and or or:
(c) Sleep and exercise are necessary for health.
Despite these, however, the verb rule seems well worth keeping. We might just add that and and or have an alternative use – listing – to that of joining verbs together. More about listing is in the post 54. Listing 1.
Secondly, the verbs joined by a conjunction have a meaning link between them. For example, a verb joined by and has the meaning link of being additional to or later than the meaning of the other verb, while one joined by but has the link of being opposite or unexpected compared to the meaning of the other verb. Other conjunction meanings can be read about by clicking on “Conjunctions” in the CATEGORIES menu to the right of this page. Note that this property of conjunctions is also shared by connectors (see 40. Conjunctions versus Connectors). What makes conjunctions special is that they combine this property with their physical linking ability.
WRONG CONJUNCTION STARTS
There seem to be two main kinds of mistake that lead teachers to discourage beginning a sentence with a conjunction. They may be illustrated by the second sentence in each of these examples:
(d) *New roads cause traffic congestion. Because drivers flock to use them.
(e) *New roads cause traffic congestion. And they are expensive.
The problem in each case is that the conjunction (underlined) has only one verb in its sentence. The other verb that it requires is in the sentence before. One possible correction is changing the conjunction into a similar-meaning connector – this is because in (d) and moreover in (e). Simpler, though, is to remove the full stop before the conjunction. It so happens that doing this will also make the conjunction a mid-sentence one instead of the first word in its sentence. Perhaps it is this effect that leads to the call never to begin a sentence with a conjunction.
One reason why it is easy to write “sentences” like the second ones above might be the fact that they are possible in spoken English. Indeed, examples like (e) are even common in some kinds of writing, such as journalism. It is only in formal written English (see 46. How to Avoid “I”, “We” and “You”) that beginning with a conjunction in these ways is rare.
WHEN A CONJUNCTION CAN START A SENTENCE
In examples (d) and (e) above, the conjunctions are both written between the two verbs that they join. Example (d), however, can also be written with the conjunction before both verbs, and hence at the start of a sentence, like this:
(f) Because drivers flock to use them, new roads cause congestion.
Sentence (a) shows the same kind of thing. Sentence (e), on the other hand, cannot be rewritten in this way; the conjunction and must always go between the two verbs. There are many conjunctions like because and only a few like and. There is no logical reason for a conjunction to be of one kind or the other, any more than there is a logical reason for some nouns being countable and some not, or some verbs being transitive and some not. You just have to remember which kind each conjunction is. Other conjunctions like and are but, yet, so, or, nor and for.
This insight allows us to make a more precise rule about conjunction positions. Firstly, it is true that conjunctions like and should not start a sentence in formal writing; instead we must either remove any full stop before the conjunction or replace the conjunction with a connector. The second part of the rule is that a conjunction like because may begin a sentence, but only when both of the linked verbs come after it, as in example (f). You cannot begin a sentence with because when it is written between the two linked verbs, as in (d).
To sum up, the rule at the start of this post may be rephrased like this: “Do not put a conjunction at the start of a sentence in formal writing unless both of the verbs linked by the conjunction are written after it”. To become more familiar with what this means, try the following exercise.
PRACTICE EXERCISE: CONJUNCTIONS & FULL STOPS
Below are some short passages with missing full stops. The task is to locate the full stops by reference to verbs and conjunctions. There are three verbs involved each time (underlined). Two should be linked together in the same sentence by a conjunction that is also present, while the third will be separated by the full stop. Answers are given afterwards.
1. After World War One ended a peace treaty was signed in a railway carriage in Versailles near Paris the peace did not last for very long.
2. Married women seek employment much more frequently today than in the past because social conditions have changed so much one change is family size.
3. There is much disagreement about the cause of global warming most scientists are convinced that human activity is responsible while a few believe in some other reason like sunspots.
4. Every sentence contains at least one verb if any additional verb is added to the sentence a joining word like a conjunction must also be present.
5. Exotic animals are being killed at an alarming rate many will become extinct unless the world’s governments manage to pass much stronger preventative laws.
6. Many young people choose to smoke although they know the long-term dangers to their health the distant future does not seem to them something worth a lot of worry.
ANSWERS: 1 = after Paris (conj = after); 2 = after so much (conj = because); 3 = after warming (conj = while); 4 = after one verb (conj = if); 5 = after rate (conj = unless); 6 = after EITHER smoke OR health (conj = although).