.At this moment the bell rang _______ the end of class.
| A．announce | B．announcing | C．announced | D．to announce |
You could see the runners very well from ______ we stood.
| A．which | B．where | C．that | D．when |
The factory was built in a secret place, around ______ high mountains.
| A．which was | B．it was | C．which were | D．them were |
Yesterday we visited a modern hospital, around _______ some fruit shops.
| A．which is | B．it is | C．which are | D．them are |
He had thousands of students, many of ______ gained great success in their own field.
| A．whom | B．them | C．which | D．who |
He asked a lot of questions, none of ______ was easy to answer.
| A．which | B．them | C．what | D．that |