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“They were doing the dishes,his wife washing while he dried“
　　请问这里while后面为什么用过去时，而his wife前边却用whishing
　　而且不是was washing,while后面不是大多用ing的吗？
　　还有“He’d acted out concern for her, he thought that it would be a nice gesture on her part not tho start up that conversatipn again “ 这怎么翻译好“gesture“在这里是什么意思？
　　谢谢！
　　能不能随便讲一下“when 与while“用法的区别？