A conjunction is merely a connecting word. It has no other function in the sentence. In most languages of European origin, clauses are joined together by conjunctions in similar ways. However, students who speak non-European-type languages often experience some problems in using English conjunctions correctly.
One conjunction for two clauses
One conjunction is enough to join two clauses.
- Although he is poor, he is honest.
- He is poor but he is honest.
- (NOT Although he is poor, but he is honest.)
- Because I liked him, I tried to help him.
- I liked him so I tried to help him.
- (NOT Because I liked him, so I tried to help him.)
Correct use of some conjunctions
Unless means if not, so it will be superfluous to introduce another not into the following clause.
- Unless you give the keys of the safe, you will be shot.
- OR If you do not give the keys of the safe, you will be shot.
- (NOT Unless you do not give the keys of the safe, you will be shot.)
Lest means that… not, and, therefore, it will be wrong to add another not in the following clause. Moreover, it should be noted that the only auxiliary verb that can be used after lest is should.
- Take care lest you fall. (NOT Take care lest you do not fall.)
- Take care lest you should fall.
- Book your tickets early lest you should miss this chance.
Than, as and that
Than is used after comparative adjectives and adverbs. As and that are not used after comparatives.
- She is taller than me.
- (NOT She is taller as me.)
- (NOT She is taller that me.)
- She has got a bigger house than I have.
As is used in comparisons of equality’. Than and that are not used in this way.
- My hands were as cold as ice.
- Your eyes are the same colour as mine.