is加过去分词是什么时态

Eight hours on a bus is no joke, is it.

坐８个小时的公交车可不是闹着玩儿的，对吧。

He is in no doubt as to what is needed.

他对需要些什么心中有数。

It is a country where corruption is rife.

这是个腐败成风的国家。