问题补充:
The computer looks old, but it just half a year ago.
A. has been bought
B. was bought
C. is bought
D. will be bought
答案:
A. has been bought
(答案→)B. was bought
C. is bought
D. will be bought
解析:考查时态。句意:这台电脑看起来旧了,但是它只半年前买的。结合语境可知下文描述的是过去的动作,故用过去时态,选B。