问几道英语题!急!1（ ）these trees were planted last year? A.By Whom B

问几道英语题!急!
1（ ）these trees were planted last year?
A.By Whom B.By who C.who D. whom (A 和B那个对?） 说明下原因
2 Doctors_____greatly in every part of the world today .
A.need B.are needed C.have needed
3.More and more waste has ___________a lot of space.We should do something to reduce it.
A.taken place B.taken away C.taken up D.taken off (说明下这道题）
各位英语高手快来帮帮我啊~~!
谢谢!我不甚受恩感激~!