Through a telescope the surface of the Mars when it comesnearer to the earth.A....Through a telescope the surface of the Mars when it comesnearer to the earth.A.can one observe B.one can observe C.can observe one D.observe one can 为什么选A不选B
问题描述：
Through a telescope the surface of the Mars when it comesnearer to the earth.A....
Through a telescope the surface of the Mars when it comesnearer to the earth.A.can one observe B.one can observe C.can observe one D.observe one can 为什么选A不选B
答
因为句子的后面部分是由when领衔的一个虚拟语气，意思是当火星靠近地球时（假设的情况），所以前面部分就应该是倒装句，can放在主语（one）的前面。
答
B
答
应该选B
如果句首还有个only才倒装,选A
only +单词、词组、状语从句位于句首,句子进行部分倒装.
Only through education can we rise in the world.
答
倒装句式。情态动词/助动词/...+主语+动词+...所以选A