To look after the sick boy is my duty为什么要用to?此句的同义句填空：——my duty —_英语解答

To look after the sick boy is my duty为什么要用to?
此句的同义句填空：——my duty —— ——after the sick boy.

人气：168 ℃　时间：2020-02-03 14:50:29

解答

不定式短语做句子的主语.
It's my duty to look after the sick boy.