问题
选择题
The little boy is dirty from head to foot because he______in the mud all morning.
A．has played
B．is playing
C．has been playing
D．was playing
答案
答案：C
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。