热情友好既是一种( ),又是一种道德行为。
A.道德义务
B.道德规范
C.道德情感
D.道德责任
参考答案:C
This cake is very sweet. You _____ a lot of sugar in it. [ ]
A. should put
B. could have put
C. might put
D. must have put
A.所
B.要
C.想
D.不