应该用哪个英语连词
Also rail travel is very safe and I am never sick on a train______I am on a ship.
A. when
B. while
C. as
D. and
我选 as （和 神马神马 一样 ）,因为我理解这句话的意思是：并且,坐火车旅游不但安全而且不会像我坐船出游一样晕车.
但是,答案是 while,好心人帮我解释解释喂神马!