Little Tommy was reluctant to tell the schoolmaster__________he had done the day before.

A．that

B．how

C．what

D．where

直立行走使古人类能 [ ]

A．扩大活动范围  

B．便于手肢行走    

C．使前肢解放，便于使用工具  

D．便于从树上摘果实