Robert is said _____ abroad, but I don’t know what country he studied in .
| A．to have studied | B．to study |
| C．to be studying | D．to have been studying |
The little boy ,out of curiosity ,_______the toy to see how it worked ,but couldn’t put it together .
| A．took apart | B．broken down | C．burst into | D．knocked off |
They have always treated us with open hands and we must be generous _______.
| A．in return | B．in addition | C．in vain | D．in case |
The chief editor expressed his doubt _______senior people would enjoy reading such magazines .
| A．which | B．how | C．whether | D．that |
As your instructor advised ,you ought to spend your time on something ______researching into .
| A．precious | B．worth | C．worthy | D．valuable |
Fancy Williams not ______the answer to such an easy question ！
| A．know | B．to know | C．knowing | D．knew |