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.
Before anything else, there is a need to be clear about what exactly conjunctions are. A fairly full description can be read within these pages in the post 174. Eight Things to Know about Conjunctions. However, it is useful here to look more closely at the common idea that a conjunction “joins two sentences into one”.
There are a number of problems with this idea. Firstly, it implies that sentences with a conjunction are derived from smaller sentences, when in reality writers may create them directly. The idea of joined sentences probably comes from the most common type of exercise for learning about conjunctions: making a single conjunction sentence out of two smaller ones. Secondly, the idea of sentence-joining is not very helpful if a student writer is unsure what a sentence is in the first place. Thirdly, this idea is not sufficient to distinguish conjunctions from other “sentence-joining” words, such as relative pronouns and participles (for a fuller list, see 30. When to Write a Full Stop).
I would prefer to say that conjunctions, rather than “joining” independent expressions together, require sentences to contain wording that would not otherwise be allowed. This extra wording is not a “sentence” but an additional verb-containing statement. Such statements would not be allowed without a conjunction (or other “joining device”) because of the rule that a new verb makes a new sentence (see 30. When to Write a Full Stop).
To appreciate how a conjunction necessitates the involvement of an extra verb, 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 any way of completing them correctly has to contain a second verb, such as dreams.
The only apparent exception to the rule that every conjunction necessitates an extra verb in a sentence is listing uses of and and 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 (for more about listing, see 54. Sentence Lists 1).
The proposed alternative to the “sentence-joining” description of conjunctions helps the first two of the problems mentioned above to be avoided: there is no reference to previously-composed sentences, and the words “verb-containing statement” give more precise guidance on what must also be added to a sentence when a conjunction is.
The third problem – the need to distinguish conjunctions from other joining devices that necessitate an extra verb in a sentence – can be addressed by highlighting another feature of conjunctions: the indication they give of how the statement after them is related to the other one in the sentence (this is one of various possibilities: another is that conjunctions do not act like nouns in the way that who, which and that do). The indication that and mostly gives about its partner words, for example, is that they are saying something additional to, or later than, what the other statement says; but indicates oppositeness or unexpectedness; and after indicates an earlier time.
This feature of conjunctions cannot be used by itself to characterise them, since it is also possessed by connectors, e.g. furthermore and however. The verb-adding property is the main means of distinguishing conjunctions from connectors: the verb necessitated by a connector must be with it in a new sentence (see 40. Conjunctions versus Connectors).
WRONG CONJUNCTION STARTS
There seem to be two main kinds of mistake that lead teachers to speak of never 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 that beginning with a conjunction in these ways is rare (see 166. Appropriacy in Professional English).
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).