答：It is the first time +从句的结构中，从句用现在完成时。It was
the first time

+从句的结构中，从句用过去完成时。没有别的时态。例如：It is the first time that Mr Smoth has visited

China. 这是史密斯先生第一次到中国来游览。

It was the first time that Mr Smoth has visited China. 译文同上。

      句型中主句it 可以用this，that，序数词first也可根据句意改变其他序数词。例如：This is the third time that

Mr Smoth has visited the Summer Palace. 这是史密斯先生第三次游览颐和园。

That was the fourth time that Mr Smoth has visited the Summer Palace.

      这是史密斯先生第四次游览长城。

【问】—Do you know our town at all? —No, it is the first time I ____ here.

A. was
B. have been
C. came
D. am coming
(全国高考，92—22)

      我选了C，对吗？

      【答】This is the first (second, third, …) time这个结构要求后面使用现在完成时，This was the

first (second, third, …) time这个结构要求后面使用过去完成时。 例如：… 当主句为将来时(It/This/That will be the first time)时，从句要用将来完成时，但用现在完成时来代替：…

       从以上可以看出两书均认为It / This / That + be + the first (second, third, …)

time之中只能使用完成时态。