David helps his mother with the housework every Saturday for abou t.
A. one and half hours
B. a half and an hour
C. an hour and half
D. one and a half hours
网友回答
A. one and half hours
B. a half and an hour
C. an hour and half
(答案→)D. one and a half hours
解析：一个半小时应表达为:an hour and a half或one and a half hours。