语法学习：语法之时态篇（三）

英语自学网

　　1)、By the time you arrive in London,we_____(stay)in Europe for two weeks.
        　　will have stayed
        　　注意arrive的一般时态表示将来的动作。
        　　2)、The first two factors must be equal for all who are being compared,if any comparison in terms of intelligence____(make)
        　　is to be made
        　　be(am/is/are;was/were)和不定式连用，可以表示多种意思，并常用于条件从句(如果想要……)。
        　　3)、While you were in London that year,the London Bridge_____(repair).
        　　was being repaired
        　　while+主语+谓语(一般过去时或过去进行时)表示过去某段时间内主语的状态或正在进行的动作，所以主句谓语应用过去进行时。
        　　4)、John is't a diligent student,for it is the third time he____(be)late,isn't it?
        　　have been
        　　在it is the third time的句型中常用现在完成时。
        　　5)、John always works in his lab and makes a lot of experiments,He___(make)experiments all afternoon and____(not finish)yet.
        　　have been making
        　　have not finished
        　　6)、It___(be)very cold lately,but it's beginning to get a bit warmer.
        　　has been
        　　注意lately，表示“近来”recently。