题目内容：

The boy who at one time had two front teeth ____is no longer the one that he used to be.
A.missing B.missed C.losing D.to lose

优质解答

A
missing是不见了,missed是错过了,losing是失去了,to lose表示失去的动作还没有发生
曾经少2颗门牙的小男孩在也不是从前的样子了