??復(fù)合句中的從句(主要指賓語從句)的時(shí)態(tài)要和主句的謂語動(dòng)詞保持時(shí)態(tài)上的一致，稱為時(shí)態(tài)的呼應(yīng)。要注意下列問題：
??1)主句謂語動(dòng)詞是現(xiàn)在或?qū)頃r(shí)態(tài)時(shí)，從句的動(dòng)詞不受影響。
??【例如】
??It is reported that a new railway is going to be built there next year. Has he told you when he is to leave for Kunming?Will you tell us how you managed to overcome the difficulties?
??2)主句謂語動(dòng)詞是過去時(shí)態(tài)，從句也必須使用過去時(shí)態(tài)。從句用過去進(jìn)行時(shí)/一般過去時(shí)，表示主、從句的謂語動(dòng)作同時(shí)發(fā)生；從句用過去將來時(shí)，表示從句的動(dòng)作在主句動(dòng)作之后發(fā)生；從句用過去完成時(shí)，表示從句的動(dòng)作在主句動(dòng)作之前發(fā)生。
??【例如】
??I didn't know you were already ahead of us.
??She asked me whether I had passed the final examination.I thought you wereshavingsa break now.Did you say you had been waiting for us?I was thinking that you wouldn't be going with us.She said they would have got everything ready by tonight.They told me that Professor Li would have been teaching here for thirty years by this winter.
??3)如果從句表示的是真理、客觀事實(shí)，則一律用現(xiàn)在時(shí)，不受主句時(shí)態(tài)的影響。
??【例如】
??Even then, people knew that tides are caused by the moon.This proved once again that the earth is round.The teacher said that the Yellow River is the second largest river in China.
??1)主句謂語動(dòng)詞是現(xiàn)在或?qū)頃r(shí)態(tài)時(shí)，從句的動(dòng)詞不受影響。
??【例如】
??It is reported that a new railway is going to be built there next year. Has he told you when he is to leave for Kunming?Will you tell us how you managed to overcome the difficulties?
??2)主句謂語動(dòng)詞是過去時(shí)態(tài)，從句也必須使用過去時(shí)態(tài)。從句用過去進(jìn)行時(shí)/一般過去時(shí)，表示主、從句的謂語動(dòng)作同時(shí)發(fā)生；從句用過去將來時(shí)，表示從句的動(dòng)作在主句動(dòng)作之后發(fā)生；從句用過去完成時(shí)，表示從句的動(dòng)作在主句動(dòng)作之前發(fā)生。
??【例如】
??I didn't know you were already ahead of us.
??She asked me whether I had passed the final examination.I thought you wereshavingsa break now.Did you say you had been waiting for us?I was thinking that you wouldn't be going with us.She said they would have got everything ready by tonight.They told me that Professor Li would have been teaching here for thirty years by this winter.
??3)如果從句表示的是真理、客觀事實(shí)，則一律用現(xiàn)在時(shí)，不受主句時(shí)態(tài)的影響。
??【例如】
??Even then, people knew that tides are caused by the moon.This proved once again that the earth is round.The teacher said that the Yellow River is the second largest river in China.