动词不定式和分词用作状语
根据对非谓语动词词性的分析，大家知道，动词不定式和分词同时还具有副词的词性特征，因此能在句子中充当状语。
与分词不同的是，动词不定式在句中做状语时，主要表示目的、结果、原因;而分词做状语主要表示时间、原因、条件、让步、结果、目的、伴随等。
一般判别二者之间的区别使用是根据不同的标志词来确定的，或者说用marker来确定它们。例如，动词不定式表示目的的有in order to, so as to。表示结果的有：so … as to, such … as to, enough to, too … to等。请看例句：
He shouted so as to be noticed.(目的)
She started early in order to avoid the rushing crowds.(目的)
Would you be so kind as to lend me your bike?(结果)
He is such a fool as to think that his idle chat can influence others.(结果)
The boy is old enough to look after himself.(结果)
His eyesight is too poor to read such small letter.(结果)
She wept to hear the news.(原因)
I rejoiced to hear that my son had been admitted into the famous university.(原因)