问题
选择题
He made another wonderful discovery, _______________ of great importance to science.
A．which I think is
B．which I think it is
C．which I think it
D．I think which is
答案
答案：A
考察定语从句和插入语。I think在句中作插入语，可以省略。Which指代先行词another wonderful discovery在句中作主语。故A正确。