5)有时一个不定式（短语）的作用接近于一个定语从句（大多表示要发生的事)：
That will be the right procedure to follow(you should follow).这将是应遵循的正当程序。
Soup, and then steak to follow, please,. 请先上汤，然后上牛排。
She was quiet for days to come. 此后许多天她都沉默无语。
That would be a rash step to take. 那可能是一个鲁莽的举动。
They were invited to the dance to take place after the wedding.他们被遨参加婚礼后的舞会。
Are you going to the banquet to be held on Friday at the embassy?你要去参加星期五在大使馆举行的宴会吗？
另外，不定式还可以和关系代词which连用作定语：
She must have time in which to pack.她必须有时间收拾行李。
They would raise some money with which to buy medicines..他们将筹集一些钱购买药品。
He also had a revolver with which to defend himself,他还有一把防身用的左轮手抢。
He only had long nights in which to study.他只有漫漫长夜可用来学习。
在个别名词后可用不定式作同位语（说明前面这个词的内容）：
Then came the order to evacuate the city.接着传来撤出城市的命令。
They had received instructions to watch him.他们接到指示要监视他。