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
D．I think which is
答案
答案：A
考查定语从句。句中I think为插入语，which指代先行词discovery，在从句中作主语。句意：他又有一个极好地发现，对科学有重要的作用。