Question

【题目】The two men promised each other to keep the secret, but finally one of them （背弃）the other.

Answer 1

【答案】turned；his；back；on
【解析】句意：这两个男人互相许诺保守秘密，但是最后他们中的一个背弃另一个。turn one's back on背弃，根据句意可知用一般过去时态，所以答案是turned his back on。