几个动词不定式的问题It was supposed to be turned in on Friday.中的不定式为何是

It was supposed to be turned in on Friday.
句子中的 was supposed to 表示应该,做情态动词should用,所以在it should be turned in on Friday.这个句子中,should be turned in是谓语部分,并不是状语,on Friday才是状语.
It is better to love and lose than never to have loved at all.
这个句子还原一下应该是To love and lose is better than never to have loved at all.所以to love and lose是主语,is better than是谓语,never to have loved at all是句子宾语.
再问： 第一个老师说是状语？
再答： 那你自己感觉一下吧。不过，这两个句子不需要强求成分的分析。第一句是注意be supposed to的用法，第二句则是学会it is better to do than to do的句型。能够学会这两个句型就可以啦~