It is the first time that he has been to America,------? 此句的

isn't it
一般情况下,主从句复合句构成的句子,反意部分和主句保持一致.
如：I told that you should not do that again,didn't i
不过,如果主句是这样的；I thing / hope / believe / imagine that.反意部分就要和从句保持一致,还要注意从句的部分前移.如：
I think that you will do that,won't you?
I don't think that you will do that ,will you