It is _____ to carry water to the mountain.

问题描述:

It is _____ to carry water to the mountain.

hard/difficult
unnecessary

difficulty(困难)或trouble(麻烦)

这个空可填的太多了. 不过只能填形容词如:hard ,happy difficult.,或表人的名词Tom.这里it是形式主语,to carry .是真正的主语,所填的是表语