Ahmed is one of the boys who always……….good work. (a) does (b) would do (c) do (d) done

You who……. Convicted, should appeal (a) has been (b) is (c) was (d) are

It is I who………. to blame for the accident. (a) is (b) are (c) am (d) were

RULE 5:
When the phrase "one of" is used, it is usually followed by a plural noun or pronoun and a singular verb.
Examples:

One of my teachers is coming
One of my sisters travels every time

The idea behind these constructions is that you have many teachers and more than one sister but you are talking about the action of one of them.

One of the___ selective marking of errors
(a) School of thought suggests
(b) Schools of thought suggest
(c) School of thought suggested
(d) Schools of thought suggests

D
C
💯💯

D is correct

One of the vice………….. in an interim capacity.
(a) President acts
(b) President act
(c) President acted
(d) Presidents acts

D is correct 💯💯

RULE 6:
When adjectives like: rich, poor, helpless, blind, young, privileged, handicapped etc are used in a sentence with the definite article coming before them, they take the plural verb.
For example:

The rich deserve respect
The poor live in misery

The helpless……………… our sympathy. (a) Require (b) requires (c) does require (d) do requires.

Rule 7:
when the phrase "a number of" is used in a sentence, it is usually followed by a plural verb while the phrase "the number of" is followed by a singular verb.

A number of students………. missed the opportunity to register. (a) is (b) has (c) have (d) do.

A
💯

C is correct

The police claim that a number of stolen cars…… recovered. a) has being (b) is being (c) has been (d) have been.

Are we still together guys?

Can we move on?

D is correct 🔥

Rule 8:
the expression "many a/an" is followed by singular noun and a singular verb.

Many a candidate ……. to realize the difference between written and spoken English. (a) fails (b) fail (c) have failed (d) are failing.
Many a man …….done without milk in…… tea these days. (a) had/their (b) has/his (c) have/their (d) had/his.