问题
选择题
The child enjoyed _____ up the wooden bricks then knocking them down.
A．adding
B．pushing
C．piling
D．forming
答案
答案：C
考查动名词和动词短语的构成辨析。 pile up (="lay" in a pile or as if in a pile) 把......放成一堆, 堆积：。Pile up作不及物动词用, 意为“积压; (若干汽车) 相撞”