单选题
In the experiment we kept a watchful eye ______ the developments and recorded every detail.
[A] in [B] at [C] for [D] on
【正确答案】
D
【答案解析】解好本题的关键在于掌握好动词keep与名词eye和介词on的固定搭配，在理解句意的同时就应该注意到“keep a watchful eye”，这样在选择时就不会走弯路。句意：实验中我们密切注视实验的进展并记录下每个细节。