They are still very cautious about _____
题型：选择题
问题：
They are still very cautious about ______ side effect the new medicine will bring about, although the experts have tried it on about 2,000 patients.
A．which
B．that
C．where
D．what
题型：选择题
They are still very cautious about ______ side effect the new medicine will bring about, although the experts have tried it on about 2,000 patients.
A．which
B．that
C．where
D．what
