主句如果是一般現(xiàn)在時(shí)態(tài)從句可以是任何時(shí)態(tài)如：1,i think he is studying English.2,i think he has finshed English homework.3,i think he is going to study English tomorrow.4,pay attention to what the teacher said.主句如果是過去時(shí)態(tài)那么從句應(yīng)該是表示過去的某種時(shí)態(tài)（過去時(shí),過去進(jìn)行時(shí),過去將來時(shí),過去完成時(shí)）.如.he said there were no classes yesterday afternoon.2.he said that he was going to take care of the baby.3,the teacher asked me if i could finish the task on time .4,he said that he had gone hong kong .如果主句是過去時(shí)態(tài)而從句式敘述某一客觀真理和事實(shí)時(shí)從句用一般現(xiàn)在時(shí).如,he said that her father is twenty-eignt years older than his.