Question

3．对不起，我忘了告诉你他不在家了．
I'm sorry Iforgot to tell you that he was not at home．

Answer 1

分析 forgot to tell．

解答 答案：forgot to tell．这里表示我忘了告诉你他不在家了．是说过去的事情，用一般过去时，忘记去做某事用forgot to do sth，告诉tell，forget的过去式是forgot，故答案是forgot to tell．

点评 动词后加to do 和doing 的意思不一样的有remember to do记住去做 remenber doing记得做过
regret to do遗憾的做 regret doing懊悔作了
forget to do忘记去做 forget doing忘记做过
try to do努力去做 try doing试试去做
help to do帮助做 can't help doing禁不住
need to do客观需要 need doing需要被做
want to do主观想要 want doing需要被做
stop to do停下去做（目的状语）stop doing停止做
go on to do接着做 另一件事 go on doing继续做