下列是四种不同情况：

　　⒈主语是人，句子里的形容词用来反映主语的“情绪”或“感受 ”，如：

　　① I am sorry to have to say good-bye to you.
　　② Tom was angry to hear Janet complain so much.
　　③ Are you glad to return to Singapore after so many years abroad?
　　④ The students were bored to listen to the same story time and again.

　　①-④里的不定式动词短语（infinitive phrases）都在修饰前面的形容词或等同语，把形容词的含义进一步带出来。

　　类似的形容词甚多，包括：happy, proud, furious, impatient ；还有形容词等同语 amazed, annoyed, ashamed, delighted 等，也适用于此。

　　⒉主语也多数是人，形容词反映主语的“意图”，如：

　　⑤ Sometimes, old staff are reluctant to help new recruits.
　　⑥ Why are you so anxious to go home?
　　⑦ I am inclined to befriend good people.
　　⑧ Bill is prone to get mad.
　　⑨ Jack is determined to go abroad for further studies.
　　⑩ It you have any problem, please let me know. I will be most willing to help you.

　　其他适用于这结构的形容词及等同语，包括：eager, reading, unwilling, disappointed 等。

　　⒊形容词反映人们对主语的“评论”，如：

　　（11） This water is good to drink.
　　（12） The salesman was rude to speak to his customers.
　　（13） Judy was bold to argue with her superior.
　　（14） Tom was thoughtless to say something like that.

　　其他可以被这样修饰的形容词还有：brave, careless, cruel, absurd, foolish 等。

　　⒋形容词反映主语的“特色”，并进一步由不定式动词或短语加以证实，如：

　　（15） The coffee you want is now ready to drink.
　　（16） Your handwriting is so cursive that it is very difficult to make it out.
　　（17） Semi-cooking rice is hard to digest in the stomach.
　　（18） Jason's articles on language learning are easy to understand.
　　（19） Such a task will be tough to perform at a short time.
　　（20） The principal's idea is simple to realise.
　　（21） This type of women is able to get angry on the slightest provocation.
　　（22） He married her, but she is in love with another man. Their relationship is too complicated to explain.