English

五官動詞（如hear, see）後的動詞不需要改變

如：I heard him chatted with his mother.

但是，當你知道整件事情（由開始到終結），動詞就需要加-ing

如：I heard him chatting with his mother.

在這裏，「我」由「他」未開始說話時直到完結說話都在場。

2008-03-23 16:30:15 補充：
Sorry, the first example should be " I heard him chat with his mother." There should be a bare infinitive after 五官動詞.