英语语法 倒装句_______, we were not going to make any concessions t

英语语法 倒装句
_______, we were not going to make any concessions to his unreasonable demands.
A. May what come
B. What may come
C. Come what may
D. What come
为什么选C
属于什么词语引起的倒装？
还有
Heat does not travel by convection in solid, because the solid does not move, ______.
A. so does a liquid
B. so a liquid does
C. as does a liquid
D. so is a liquid
为什么是C？不用so吗