（1）所修饰的名词在逻辑上与不定式成动宾关系
例句
a. She has four children to take care of .
b. I had no place to live in.
c. You just regard me as a thing, an object to look at, to use, to touch, but not to listen to or to take seriously.
你只把我当作一件东西，一件任你看、任你使用、任你抚摸的东西，但你就是不听我说话，不认真对待我。
d. I gave the kid a comic to read.
e. I have no partner to speak English with.
f.I need a pen to write with.
g. I need a piece of paper to write on.
注意：1）不定式作定语时，一般用主动形式表达被动含义。
2）不定式中的动词后不能再加宾语。
a. I gave the kid a comic to read it.*
b. I need something to eat it.*
3）不定式中的动词后的介词不能省略。
a. I have no partner to speak English.*
b. I need a pen to write.*
（2）被only， last， next， 序数词以及最高级形容词修饰的名词常用不定式作定语（重点内容）
a. I don’t think he is the best man to do the job.
我认为他并不是做这个工作的最佳人选。
b. The next train to arrive is from New York.
下一列到达的火车是从纽约开来的。
c. Clint was the second person to fall into this trap.
克林特是第二个掉进陷阱的人。
d. Clint was the only person to survive the air crash.
克林特是这次空难事故中唯一的幸存者。