Case by case.

看了一下绿卡还有不到半年就过期了，上网一看，renew绿卡也要钱。不如把这钱来入籍算了。不知道赶得及不。

-Yes.

Read this link for some information:

http://www.alllaw.com/articles/nolo/us-immigration/applying-citizenship-expired-green-card.html