问题
选择题
In the experiment we kept a watchful eye ________ the developments and recorded every detail.
A．in
B．at
C．for
D．on
答案
D
因为keep an eye on…是习语，意为“密切注视…”。
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In the experiment we kept a watchful eye ________ the developments and recorded every detail.
A．in
B．at
C．for
D．on
D
因为keep an eye on…是习语，意为“密切注视…”。