I think the best way to keep healthy is _____exercise

问题描述:

I think the best way to keep healthy is _____exercise
A.for
B.through
C.in
D.with

选B
翻译:我认为保持健康最好的办法是通过锻炼.
for意思是为了
in和with都是介词没有“通过”的意思
through也是介词,(指方法、手段等)经由,通过什么方法手段做成某件事,因而选择B