Question

Don't you know it's the first time he_this kind of meeting?A attends B attended C has atteng

Don't you know it's the first time he_this kind of meeting?A attends B attended C has atteng D is attending

Answer 1

B attended
在it's the first time 这个句型中，主句是现在时时，后面从句要用一般过去时。
AD是现在时，肯定不行。 C是完成时，但是attend是瞬间动词，一般不用完成时。
所以选B

Answer 2

A

Answer 3

C 有个句法就是it is XX time sb has done sth..

Answer 4

C
It is/was the first time……是与完成时在一块用的。