问题
选择题
＿＿＿the people have become the master of their own country＿＿＿science can really serve the people.
A．It is only then； that
B．It was that； when
C．It is only when； that
D．It was when； then
答案
答案：C
该题为强调句型，强调only when引导的时间状语从句。