问题
选择题
_______ the people have become masters of their 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
C
本题考查强调句型。被强调部分为状语从句only when the people...country；that为强调句型的引导词。