帮忙划分一下括号内的句子成分（即主语/宾语/谓语/表语/状语/补足语/同位语）
we are (students)
seeing is （believing)
time is (up),the class is(over)
the true is (that he has never been abroad)
顺便简单的帮我理清一下谓语表语状语补足语同位语
还有i'm a American boy 谓语是？