He is known _____ a scientist and famous _____ his research on rice.
| A．for; as | B．for; for | C．as; for | D．as; as |
Great changes __________ in our hometown in the past twenty years..
| A．have been taken place | B．has been taken place |
| C．have taken place | D．were taken place |
John, look at the time. ________ you play the piano at such a late hour?
| A．Can | B．Need | C．May | D．Must |
He looked as though he _________ a ghost（鬼）.
| A．saw | B．has seen | C．have seen | D．had seen |
He stood for an instant with his hand still ___________.
| A．raised | B．raising | C．rose | D．risen |
_____ is known to all, the age _______ children can go to school is seven.
| A．What; which | B．It; when | C．As; at which | D．Which; when |