动词不定式和现在分词在作宾语补足语时的区别.例如:she decided to take the exam.能否说

首先,你举的例中to take the exam是动词不定式做宾语；其次我们可以说she decided on taking the exam.
不同的动词,用不同的动词不定式或现在分词做宾语,需要专门记忆；
个别动词既可接动词不定式有可接现在分词（我们更多时叫作动名词）：like to do/doing sth.不定式表示偶尔或具体的行为,现在分词表示经常,抽象的行为.
i like reading. i like to to read this book .
动词不定式和现在分词做宾语补足语,区别如下：
see sb. do sth/see sb. doing sth
i saw him play football yesterday.
i saw him playing football at five.
动词不定式表示动作完成及过程；动词现在分词表示动作正在进行.