Partly---his wife's being there,I said nothing about it when we ate together. A,because of B,fo

Partly---his wife's being there,I said nothing about it when we ate together. A,because of B,for

选A. partly because (of) ：部分原因，部分是因为
partly for: 部分是为了
“当我们一起吃饭时我丝毫没有提及此事，部分原因是他老婆在场。”

你好！ 选A，FOR一般后面是加完整整句，而because of 后面一般加名词性词组 如果对你有帮助，望采纳。