—This returned scholar has become one of the top experts in this field.
—Yes, I know him very well. He ______ for ten years at an institute in the USA.
A. has worked B. has been working C. worked D. had worked
.– How much did you pay for that?
--- I paid _____ that you paid.
| A．half the money | B．half | C．the halves | D．a half |
.More than one girl _____, as we expect.
| A．has come | B．had come | C．came | D．have come |
As we all know, two thirds of the earth’s surface is water, ___ a lot of fish.
| A．provided | B．providing | C．which provides | D．it provides |
Jack is the ______- child in the family; he wants to have a brother.
| A．one | B．single | C．only | D．separate |
Only in this way, directed by the teacher, ______work out the problem the day before.
| A．had they | B．they could | C．could they | D．did they |