我們知道，在英文中，不定式to do 可以作名詞的后置修飾語，構成三種搭配關系：主—動關系、動—賓關系和同位關系。其實，作名詞的后置修飾語，除了用to do，還可以用“介詞+doing”的形式。

一、名詞+to do

有些名詞，其后的修飾語一般用to do。這些名詞有：ability, agreement, ambition, anxiety, curiosity, disposition, mind, obligation, permission, refusal, reluctance, temptation, tendency和wish等。

They have no ability to win the game. 他們沒能力贏得這場比賽。

We have signed an agreement to rent the house. 我們已簽下了租房協議。

She is under no obligation to buy anything for him. 她沒必要給他買東西。

Wood has a tendency to swell if it gets wet. 木材遇潮易脹。

二、名詞+介詞+doing

有些名詞，其后通常接“介詞+-ing分詞”作后置修飾語，而一般不接to do，例如：aptitude, delay, difficulty, excuse, experience, interest, genius, habit, hope, idea, method, movie, object, passion, plan, possibility, skill和success。

The little boy has a great aptitude for finding something new. 這個小男孩有發現新奇事物的才能。

Miss Yang has much experience in teaching English. 楊老師在英語教學方面經驗豐富。

He has little hope of passing the exam. 他沒有希望通過考試。

We must improve the method of teaching English. 我們必須改善英語教學的方法。

三、“名詞+to do”和“名詞+介詞+doing”

除了以上兩種情況所介紹的名詞外，還有一些名詞，后面接“名詞+to do”和“名詞+介詞+doing”兩種形式皆可以，意義上也無區別。如：attempt, chance, effort, freedom, intention, necessity, opportunity, reason, time和way。

Although they had made an effort to finish the task, they failed at last.

=Although they had made an effort at finishing the task, they failed at last.

盡管他們已盡力完成任務，最終還是失敗了。

There is no necessity to buy so many things.

=There is no necessity of buying so many things. 沒必要買這么多東西。

I hope that I can have the opportunity to speak to you alone.

=I hope that I can have the opportunity of speaking to you alone.

我希望可以有機會跟你單獨聊聊。