宾语从句:(that常可省略)
1.用that引导:I'm sure (that) she will come.
2.用whether/if引导:表"是否"(但if不可放在句当"是否")
I don't know whether it will be fine tomorrow.
3.用疑问词引导(what,when,where,which,how,who,whose,why):
He didn't understand why they were laughing.
注:宾语从句中如果表达的客观真理或是事实,必须得用一般现在时来表达.如:
I was told that the earth moves aroung the sun.