Gun control is a subject ________ Americans have argued for a long time．

about which

about whom

what

that

They took care of the old man ________ son lost his life in the fire．

who

of whom

whom

whose

My family climbed up the hill, ________ we had a picnic．

on the top of which

on its top

on the top of that

on the top of it

I'll never forget the three days ________ I spent on the seaside with my friends．

which

when

during

on which

He is a man with rich experience, from ________ much can be learned．

which

whom

where

what

After living in Paris for fifty years he returned to the small town ________ he grew up as a child．

which

where

that

when

________ people are standing outside the office．________ people there is at least over 1000．

A number of; A number of

The number of; The number of

A number of; The number of

The number of; A number of

The lady insisted that the young man ________ her wallet and insisted on ________ to the police station at once．

had stolen; be sent

should steal; sending him

had stolen; sending him

should steal; sending

Whenever we are in ________, we must never lose ________, but try to think of the way out．

the trouble; our heart

troubles; hearts

trouble; heart

trouble; our heart

Someone is ringing the doorbell．Go and see ________．

who is he

who he is

who is it

who it is