这些名词均含“命令”之意。
command : 较正式用词，强调权威性、全局性和强制性。
- You will run forward at (= when you hear) my command.
听到我的命令你们就向前冲。 - When I give the command, fire!
我一下命令就开火！ - He hated being in the army because he had to obey commands.
他讨厌当兵，因为当兵必须服从命令。
order : 普通用词，侧重指具体的命令。
- The soldiers fired as soon as their commander gave the order.
指挥官一声令下，士兵们立即开火。 - Soldiers must obey orders.
军人必须服从命令。 - What are your orders?
你接到了什么指示？ - My orders are to search everyone's bag as they come in.
我接到的命令是搜查每个进来的人的包。 - The road was closed all day by order of the police.
按照警方的命令，这条路全天封闭。 - Clean up this room immediately - and that's an order!
立刻清理好这间屋子——这是命令！
direction : 正式用词，指口头或书面的指示或命令。内容不一定详尽，语气较缓和，不太强调强制性。也可指指导性的说明。
- I couldn't understand the directions on the packet.
我看不懂包装盒上的说明。 - He will be giving/issuing directions to judges on sentencing in the next few days.
过几天他要向法官发布审理说明。
instruction : 书面用词，指不容违反、不容推翻的命令。也多指包含具体说明的指示。
- The police who broke into the house were only acting on/under instructions.
警察破门而入只是奉命行事。 - He gave me strict instructions to get there by eight o'clock.
他命令我必须在8点以前到达那里。
