When she was very young, my sister already knew where her toys.
选择一项:
a. put
b. to put 解析:[to put]我的妹妹还很小的时候就已经知道把她的玩具放在哪里。这里where引导动词不定式短语做动词knew的宾语。
c. putting
d. putted
出自:广东开放大学学位外语(本,23春)