四道困惑的英语题

四道困惑的英语题
There were five ferries ____ people away from Manhattan to Weehawken.
A.transporting B.transforming C.transferring D.transplanting
C为什么不行?转移人?
____modeling business is by no means easy to get into ,the good model will always be in demand.
A.while B.Since C.As D.If
B.
Other scientists who study living-things ____ the biological sciences.
A.work with B.put off c.take up d.get in
c解释为“从事”为何不可?D引申为“进入某领域”可否?
Sometimes patients sufferings from severe pain can be helped by "drugs" that aren't really drugs at all ____sugar pills that contain no active chemical elements at all
A.or rather b.rather than c.but rather d.other than
or rather 与 but rather 都有“更确切地说 ”之意,有何区别?