The child is much too young; I object him alone at home.A. to leave B. leaveC. leavingD.

问题补充：

The child is much too young; I object him alone at home.

A. to leave

B. leave

C. leaving

D. to leaving

答案：

A. to leave

B. leave

C. leaving

(答案→)D. to leaving

解析：考察固定搭配。固定搭配object to sth/doing sth反对做某事；其中的to是介词，后面接名词或者动名词做宾语。句意：这个孩子太小了，我反对把他一个人留住家里。故D正确。