English: Rules Of Grammar - Part - 4

1. ‘Scarcely’ and ‘hardly’ are followed by ‘when’ and not by ‘than’.

Uses -
I had scarcely entered the room than the phone rang. (Incorrect)
I had scarcely entered the room when the phone rang. (Correct)

2. ‘Though’ is followed by ‘yet’ and not by ‘but’.

Uses -
Though he is poor but he is honest. (Incorrect)
Thought he is poor, yet he is honest. (Correct)

3. ‘No sooner’ is followed by ‘than’.

Uses-
No sooner had I entered the class when the student stood up. (Incorrect)
No sooner had I entered the class than the students stood up. (Correct)

4. ‘Lest’ must be followed by ‘should’.

Uses-
Read regularly lest you will fail.
Read regularly least you should fail.

5. ‘such’ is followed by ‘as’.

Uses-
He is such a writer that everybody should read his books. (Incorrect)
He is such a writer as everybody should read his books. (Correct)

6. ‘So’ is followed by ‘that’.

Uses-
Sarita was popular with her classmate that she always had Some people coming to her for advice. (incorrect)
Sarita was so popular with her classmate that she always had Some people coming to her for advice. (correct)

7. ‘Unless’ express a condition. It is always used in the negative sense. Thus ‘not’ is never used with ‘unless’.

Uses-
Unless you do not labour hard, you will not pass. (Incorrect)
Unless you labour hard, you will not pass. (Correct)

8. until expresses time. It has a negative sense and thus ‘not’ should never be used with it.

Uses-
Wait here until I do not return. (Incorrect)
Wait here until I return. (Correct)

9. ‘Since’ indicates a point of time and ‘for’ stands for the length of time.

Uses-
He has been reading the book since two hours. (Incorrect)
He has been reading the book for two hours. (Correct)

Two hours is a length of time and thus ‘for’ is correct.

It has been raining for Monday last. (Incorrect)
It has been raining since Monday last. (Correct)

10. ‘as if’ used to convey the sense of pretension. When ‘as if’ is used in this sense, ‘were’ is used in all cases, even with third person singular.

Uses-
He behaves as if he was a king. (Incorrect)
He behaves as if he were a king. (Correct)

11. Use of should and would

Should and would are past tenses of shall and will and in general express the same ideas as do shall and will. except that should sometimes means ought.

Uses-
You should not speak in that way.
We should respect our parents.

You should visit them now.
You would not enjoy that experiences either.

I would not allow such as agitation.
Every day I would go jogging in the morning.

Note: In first person, always use should with the words glad, pleased, like etc.