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1.現在進行時,be+動詞ing
2.過去進行時,were/was+動詞ing
3.adj+動詞ing,一般的adj后都是不定式的形式,但有2個詞除外.busy+動詞ing,worse+動詞ing
4.介詞后的動詞都+ing
5.to分介詞和小品詞,小品詞后+to do，而介詞后就＋ing,如：be used to doing、prefer doing to doing、make a contrubution to doing、look forward to doing、pay attention to doing、accroding to doing、belongs to doing……
6.動詞+動詞ing，如：admit, advice, anticipate, appreciate, avoid，consider, delay，deny，dislike, enjoy，escape，excuse, fancy，favor, finish，imagine，include , keep, mind，miss, postpone, practise，prevent , propose, resist, risk, suggest……