问题补充:
The film for half an hour.
A. has begun
B. has been on
C. hasn’t begun
D. began
答案:
A. has begun
(答案→)B. has been on
C. hasn’t begun
D. began
解析:句意:电影已经开始半个小时了。根据句意可知,电影已经开始了,但是begin 是一个瞬间性动词,它不能和一段时间状语连用,而这句话中有for half an hour,所以可以排除A、C和D。故选B。