Explanation

The passive voice of the sentence "Have you laughed at them?" is: Have they been laughed at by you?

Explanation

A Joint Venture Account is a Nominal Account.

A joint venture is an arrangement in which two or more parties agree to pool their resources for the purpose of a specific task or transaction. 

Explanation

Put Off means postpone.

Put off means منسوخ کردینا

Explanation

Frugal and parsimonious are synonyms of each other and bear the meaning 'being stingy' or 'sparing'.

Similarly, joy and ecstasy are related to happiness.

Explanation

Air is the most essential thing for life زندگی کیلئے سب سے اہم چیز ہوا ہے 

Generally, article the is used for a superlative degree of adjective.

Explanation

We generally use as to refer a profession.

He began his career 20 years ago as a doctor means انہوں نے اپنے کیریئر کا آغاز 20 سال قبل بطور ڈاکٹر کیا تھا۔

Explanation

Explanation

The corrected sentence would be: "The teacher is popular with his students."

This means that the students like and admire the teacher.

"استاد اپنے طلباء میں مقبول ہوتا ہے۔"

Explanation

Could is a modal verb.

Could can be used for polite/formal request.

Could I have some more tea please?

کیا میں مزید چائے پی سکتا ہوں؟

Explanation

In passive voice, the object of the active sentence becomes the subject.

"A song is not sung by him" is the correct passive construction for the present tense.