It seems（that）he was late for the train!表语从句,that可以省略吗?

It seems（that）he was late for the train!表语从句,that可以省略吗? it seems that he is ill与it seems that he were ill 的区别? It seems that he has known that He seems to ____ ____ that It seems that he is happy.改为同义句（提示：He ______ ______ _____________happy.） it seems that he has----- (succeed )solved that problem. It seems that he knows everything.为什么要it开头? It seems that he has a lot of friends（同义句It seems that he has a lot of friends（同义句转换） It seems that he has had a cold转换He seems　＿　＿　＿acold. 同义句It seems that he is ill He seems ____ ___ill [同义句} ____ he knew nothing about her.A.It seems that B.It seems as if It seems that he has passed the exam(改为简单句） it seems that he is a teacher(改同义句）____seems____ ______a teacher It seems that he doean't have a computer(同义句） It seems that he has bought something interesting.（改为简单句） It seems that he's very polite.(改为同义句） ___seems___ ____very polite. It seems that he is very happy today等于什么 It seems that he is unhappy 同义句He___to___unhappy. It seems that he failed the exam这句话对吗