_____they are very tired, they feel happy because they’ve finally finished their project.
- A.Because
- B.Until
- C.Although
- D.Since
答案
正确答案:C
知识点:状语从句

because“因为”,until“直到”,although“尽管”,since“自从;因为”。句意为“……他们很累,但是他们感到很开心,因为他们终于完成了他们的项目”,可知填“尽管”比较合适。所以答案选C。

略
