问题补充：
They looked each other and kept their secrets themselves.
A. for; to
B. at; for
C. at; to
D. out; at
答案：
A. for; to
B. at; for
(答案→)C. at; to
D. out; at
解析：look at 看：look for 寻找；look out当心；keep ones secrets to sb 信守承诺。句意：他们相互看着对方，对自己信守承诺。故选C.
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