The little boy is dirty from head to foot because hein the mud all morning.A. has played 　

问题补充：

The little boy is dirty from head to foot because hein the mud all morning.

A. has played

B. is playing

C. has been playing

D. was playing

答案：

A. has played

B. is playing

(答案→)C. has been playing

D. was playing

解析：从is dirty from head to foot和all morning判断应用一直在玩。现在完成时态和现在完成进行时态都是说明动作由过去开始，该动作延续到现在。