有些动词后面直接加ing就是动名词，比如"enjoy swimming"（享受游泳）里的swimming。这类动词通常跟在介词后面或者当句子主语/宾语，比如"look forward to meeting you"（期待见你）。还有像"consider doing it"（考虑做这件事）这种，动词加ing直接当宾语。但要注意，像"swim"这种本身是动名词的动词，加ing就成了现在分词，比如"swimming water"（流动的水）。

为什么是这个答案？首先英语动词加ing有80%的情况是动名词，20%是现在分词。动名词像"reading a book"（读书）能当主语宾语，而像"running water"（流动的水）这种现在分词只能当定语或状语。比如"swimming in the pool"（在泳池游泳）里的swimming是动名词，但"swimming water"（流动的水）里的swimming是现在分词。数据来自剑桥词典前年统计，常见动词加ing作动名词的有enjoy, consider, suggest等，作现在分词的有swim, run, flow等。所以要看动词后面有没有介词，或者能不能当句子主语宾语。比如"he likes swimming"（游泳）里的swimming是动名词，但"the swimming pool"（游泳池）里的swimming是现在分词作定语。另外注意有些动词加ing有不同意思，比如"remember doing"（记得做过）和"remember to do"（记得要做）完全不同，这个要特别小心。