He made another wonderful discovery, ___
题型:选择题
问题:
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 it is
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 it is