the boy ____ under the tree is my neighbour's son.

问题描述:

the boy ____ under the tree is my neighbour's son.
A.laying
B.lies
C.lying
D.lay

C
lie 躺在、位于(动词原形),正躺在树下,用现在分词表示正在进行的动作,lie的现在分词-》lying,因此选C
lay是下蛋\产卵;搁放,或是lie的过去式,所以不对