完成时态用于最高级的句型

英文常常把现在完成时态用于这样的结构中：
                         ”最高级或序数词+名词+that从句+现在完成时谓语“
也就是说：在形容词最高级修饰的名称后面若接有一个that从句，此时从句的谓语要用现在完成时态。
I don't mean to offend you,madam.But this is the ugliest baby I've ever seen in my life.
在日常口语中，要告诉别人这是自己的”最怎么样“的经历时，就要用现在完成时态。比如：
This is the most interesting novel that I've ever read.
This is the hardesr job that I've ever done.
在这个句型结构中，除了用最高级外，还可以用序数词来修饰名称。此时，从句的谓语同样要用现在完成时态。
A：This is the tenth cup of coffee that I've drunk this evening.
B : How are you going to be able to fall asleep later if you keep on like this?
在口语中，如果要告诉别人自己是第几次来某地方，都要用现在完成时态。
This is the first time that I've come to Beijing.这是我第一次来北京。
This is the third time that I've come to Paris.这是我第三次来巴黎。
最后，在上述句型中，主句的谓语若是一般过去时，that后面的句子的谓语要用过去完成时态。
This was the tenth cup of coffee that I had drunk that evening.