问题补充：
Only when possible to settle the problem.
A. our teacher comes will it be
B. does our teacher comes will it be
C. our teacher comes it will be
D. has our teacher come will it be
答案：
(答案→)A. our teacher comes will it be
B. does our teacher comes will it be
C. our teacher comes it will be
D. has our teacher come will it be
解析：考查倒装句：句意：只有当老师来了，才可能解决问题。Only后面接时间状语从句的时候，后面的从句倒装，从句中不能倒装，will放在it前面，选A。
