After the equipment was introduced; they produced_______ machines this year as the year before.
| A．as twice many | B．as many twice |
| C．twice as many | D．twice many as |
While______ in Scotland, he made friends with the native there.
| A．working | B．worked | C．he works | D．he is working |
--- Have you really been to visit the Bird’s Nest in Beijing?
---- I ______ it last summer vacation.
| A．do visited | B．do visit | C．did visited | D．did visit |
Ten minutes had been made full ____ of ____ the problem.
| A．using; studying | B．use; to study |
| C．to use; to study | D．use; studying |
These flowers are pleasant to ______.
| A．be looked at | B．look at | C．looking at | D．for looking at |
Tom’s dog became ill and died,____ made him very lonely.
| A．this | B．that | C．which | D．what |