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．has been playing
C．is playing
D．was playing
答案
答案：B
考查时态。句意：因为他整个上午都在泥中玩耍，这个小男孩从头到脚都很脏。结合语境可知从句中描述的是现在已经完成的过去正在进行的动作故用完成进行时态，选B。