高等教育 / 大学英语1
(单选题) Scientists photographed for the first time ever _ _ _ _ _ wild gorillas used a stick to test the depth of a pool before getting into it, according to a recent study.
A、which
B、what
C、that
D、when
A、which
B、what
C、that
D、when
参考答案：
佳题速递：