核算国内生产总值时，通常采用的方法有（）。
A.生产法
B.剩余法
C.支出法
D.收入法
E.趋势法
参考答案：A, C, D
He _____ football regularly for many years when he was young. [ ]
A. was playing
B. played
C. has played
D. had played
