不定式的肯定式和否定式都可以用作定语，用法是一样的，只是意思不同。下面是不定式否定式作定语的几个例子，注意体会：
He had the tact not to mention her divorce. 他很乖巧，避免提及她离婚的事。
We have an agreement not to talk about some things. 我们有一个协议，不谈某些事。
We were the only team not to choke when it came to the crunch. 我们是惟一一支没在关键时刻因胆怯而失手的队伍。