Explanation

The phrase "By the time I picked up the phone" indicates that one past action (they rang off) was completed before another past action (I picked up the phone).

Therefore, the past perfect tense "They had rung off" is grammatically correct.

Explanation

We use the preposition "on" with specific days or dates.

Since "my birthday" is a specific day, the correct sentence is:

Khalid forgot to wish me on my birthday.

Explanation

The correct preposition used with "enrolled" in this context is "for."

We say: "enrolled for a course/class."

So the correct sentence is: You have enrolled for more than one class.

Explanation

The complete sentence is: "He has done a great service for me."

We commonly use the preposition "for" after "service" when indicating the person who benefits from the service rendered

Explanation

We use "in the night" to refer to a general time during the night.

Example: He woke up in the night.

We use "at night" for general habits (e.g., I work at night), but with "the night," "in" is correct here.

Explanation

As is the error.

A possible correct version of the sentence would be:

"The weather being warm, we stayed in."

This is a type of participial phrase.

Explanation

The error is So.

The correct sentence should use a different conjunction or structure to indicate the consequence of bees making honey:

"Bees make honey, which we eat."

"Bees make honey, and we eat it."

"Bees make honey for us to eat."

"So" is used to show a direct cause and effect (e.g., "It was raining, so I took an umbrella").

Explanation

The error is Is.

The correct sentence should be: "Tell me what your hobby is."

It is an indirect question.

The correct grammatical structure requires the subject ("your hobby") to come before the verb ("is") in the embedded clause, following the standard declarative sentence word order.

Explanation

The error is Do.

The correct sentence should be: "I would like to know where you live."

This is an indirect question.

In indirect questions, the standard subject-verb word order is used after the question word ("where").

Explanation

The error is Will go.

The correct sentence should be: "If I go to bazaar, I will buy a new pair of trousers for you."

This is a type 1 conditional sentence, which expresses a real possibility in the future.

The structure requires the simple present tense in the "if" clause and the future tense in the main clause.

You do not use "will" in the "if" clause.