Excuse me,what did you say?I said that I like your shirt.

that 可省
不可省的情况：
1.在主语从句、表语从句、同位语从句中（除宾语从句）,that 不能省.如：
That the seas are being overfished has been known for years.（主语从句）
The truth is that nobody knows who invented eyeglasses.（表语从句）
We have to face the fact that land is fragile.（同位语从句）
2.在agree,argue,hold,learn,observe,remark,suggest,indicate,conceive这种比较正式的书面语的谓语动词后,that不可省略.如：
Both candidates agree that the biggest local concern is unemployment.
Studies indicate that we have a limited amount of self-control.
3.在it作形式宾语的宾语从句前,that不可省.如：
They found it difficult that they would finish their work in two days.
4.在由and或or所连接的两个宾语从句时,第一个从句中的that可以省；而第二个从句中的that不能省.
It is depressing to think (that) life is purposeless and that evolution has no higher destination.
通过以上对that可省可不省的情况的总结,相信对that在从句中的作用有了更清晰的认识,但要记住一点,GMAT中宾语从句引导词that是不能省的,高中语法只要记住不能省的情况就可以了.