看到问题我回忆里一下，发现自己平时跟老外说话，提到join会有时join sth.有时join in sth.老外从来没有表示异议。刚又特意查了词典，发现“join the party”和“join in the research”，楼主能体会出区别吗？还是根本没区别呢？我也不清楚了呵呵。不过词典里倒是有另一个case，我觉得带“in”比不带更顺嘴：They danced and danced until a lot of us joined in.他们不停地跳着舞, 直到我们中间许多人都参加了进去。They came out for their morning exercise.I also joined in.他们出
