1. 表示“命令”“吩咐”，可用作动词或名词;注意相应的宾语从句、表语从句、同位语从句等用虚拟语气(should+v.)。如：
He ordered that the goods should be sent by air. 他命令货物得空运。
His order is that all the soldiers should start at once. 他的命令就是所有的士兵马上出发。
He gave orders that the work should be started immediately. 他发出指示要立即开始工作。
后接宾语从句时有时可以换成不定式或过去分词的复合结构。如：
老板吩咐这工作必须按时完成。
正：The boss ordered the work (to be) finished in time.
正：The boss ordered that the work (should) be finished in time.
2. 表示“订购”，也可用作动作和名词，注意以下常用句型：
我向这家工厂定购了500双鞋。
正：They ordered 500 pairs of shoes from the factory.
正：They placed an order for 500 pairs of shoes with the factory.
3. 表示“点菜”，也可用作名词(可数)或动词(及物)。如：
May I have your order, please? 请问你要点什么菜?
What shall I order for you? Steak or fish? 我给你叫什么菜? 是牛排还是鱼?
4. 表示“顺序”“秩序”“整齐”，只用作名词(不可数)，注意以下常见搭配：in order(按序，整齐)，in good (bad) order (有 / 无条理)，keep order(维持秩序)，out of order(坏了，不运转)，in order of size (date, time)(按大小、年代、时间顺序排列)，等。
5. 比较 in order to与in order that：两者都表示目的，但前者后接动词原形，后者后接句子。如：
She learnt typing in order to help her husband with his work. 她学习打字是为了帮助她丈夫工作。
I bought a new car in order that my wife might learn to drive. 我买了一辆新车，以便我妻子学习驾驶。
注意，in order to do sth 的否定式是in order not to do sth，而不是not in order to do sth。如：
They must have worn gloves in order not to leave any fingerprints. 他们一定戴上了手套，以防留下指纹。
如果主句与从句主语相同，in order to 与 in order that 通常可以互换。如：
我观察他，是要更多地了解他。
正：I watched him in order to know more about him.
正：I watched him in order that I could know more about him.
如果主句与从句主语不相同，in order to与in order that有时也可以互换，但要注意在in order后接for sb to do sth。如：
我马上告诉他这个消息，以使他安心。
正：I told him the news instantly in order that he might ease his mind.
正：I told him the news instantly in order for him to ease his mind.
