不定式動詞（the infinitive）或不定式動詞短語（the infinitive phrase）的功能之一是修飾動詞。這種具副詞功能的不定式動詞或短語，和分詞短語一樣，可以在句子中發(fā)揮不同作用，包括“目的、結(jié)果、原因、比較”。
Ⅰ表示目的，如：
● To learn a language well, one must make great efforts and work with tenacity.
● To prevent war, big or small, it is important to promote international understanding.
● Zhiqiang came to my office to ask a question.
● The warden walked around the building to see that nothing went wrong. 表示“目的”的不定式動詞短語可以在句首，也可以在句尾。在句首時，可以加上“in order”；在句尾時，可以附以“so as”，如：
● In order to win the table-tennis match, the players practised day and night.
● Betty worked very hard so as to catch up with the rest of the class.
Ⅱ表示“結(jié)果”，如：
● Indonesia beat Denmark to take the first place in the badminton tournament.
● Sam passed the final examination to qualify for the next phase of study.
表示“結(jié)果”的不定式動詞短語出現(xiàn)在句尾，而且經(jīng)常以預(yù)料不到的情況出現(xiàn)，如：
● After the short meeting, they separated, never to see each other again.
● Li Qi rushed to the bus station as fast as he could, only to find the last bus already gone.
Ⅲ表示“原因”，如：
● I was really a fool not to listen to you at that critical moment.
● No gambler wins in the end and you would do well to avoid gambling of all forms.
Ⅳ表示“比較”，如：
● She opened her lips, as though to speak.
● Her friend looked at him, as if to have something important to tell him.
必須注意的是，含“比較”意思的不定式動詞或短語前面要用“ as if ”或“as though”引導(dǎo)。
除了直接修飾謂語動詞之外，不定式動詞或短語還可以和介詞“ with, for”連用，如：
● With nobody to help, the poor man worked late into the night.
● The police removed the road block for the cars to pass.
● With little money to be used, Judy could not buy any more expensive things.
● For a lesson to be fruitfully taught, the teacher must make thorough preparations before going to class.
● For such a scheme to work well, the staff concerned have to be devoted and effective.
● With limited power to be exercised, the new manager could get nowhere.
Ⅰ表示目的，如：
● To learn a language well, one must make great efforts and work with tenacity.
● To prevent war, big or small, it is important to promote international understanding.
● Zhiqiang came to my office to ask a question.
● The warden walked around the building to see that nothing went wrong. 表示“目的”的不定式動詞短語可以在句首，也可以在句尾。在句首時，可以加上“in order”；在句尾時，可以附以“so as”，如：
● In order to win the table-tennis match, the players practised day and night.
● Betty worked very hard so as to catch up with the rest of the class.
Ⅱ表示“結(jié)果”，如：
● Indonesia beat Denmark to take the first place in the badminton tournament.
● Sam passed the final examination to qualify for the next phase of study.
表示“結(jié)果”的不定式動詞短語出現(xiàn)在句尾，而且經(jīng)常以預(yù)料不到的情況出現(xiàn)，如：
● After the short meeting, they separated, never to see each other again.
● Li Qi rushed to the bus station as fast as he could, only to find the last bus already gone.
Ⅲ表示“原因”，如：
● I was really a fool not to listen to you at that critical moment.
● No gambler wins in the end and you would do well to avoid gambling of all forms.
Ⅳ表示“比較”，如：
● She opened her lips, as though to speak.
● Her friend looked at him, as if to have something important to tell him.
必須注意的是，含“比較”意思的不定式動詞或短語前面要用“ as if ”或“as though”引導(dǎo)。
除了直接修飾謂語動詞之外，不定式動詞或短語還可以和介詞“ with, for”連用，如：
● With nobody to help, the poor man worked late into the night.
● The police removed the road block for the cars to pass.
● With little money to be used, Judy could not buy any more expensive things.
● For a lesson to be fruitfully taught, the teacher must make thorough preparations before going to class.
● For such a scheme to work well, the staff concerned have to be devoted and effective.
● With limited power to be exercised, the new manager could get nowhere.