问题
选择题
It was __________ he took off his dark glasses __________ I realized he was a famous singer.
A．until，that
B．not until，that
C．not until，when
D．when，then
答案
：B
：考查强调句型。强调句型：it is/was本强调成分that/who其它成分；本题强调时间状语not until he took off his dark glasses;句意：直到他摘掉眼镜，我才意识到他是一个著名的歌手。故B正确。