當主句謂語動詞為一般現(xiàn)在時的時候,賓語從句可以根據(jù)實際情況運用各種時態(tài),當主句謂語動詞為一般過去時的時候,從句必須用相應的過去時態(tài)（客觀真理都用一般現(xiàn)在時）.
例：He says that he lost his book yesterday.
He says that he will go shopping tommorrow.
He said that he would go shopping the next day.
He said that you were a teacher.
He said that the earth travels around the sun.(客觀真理)