command 较正式用词，强调权威性、全局性和强制性。
order 普通用词，侧重指具体的命令。
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。
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。
参考例句
1. He commanded the soldiers to shut the gate. 他命令士兵们把大门关上。
2. They helped us by every means at their command . 在他们的指挥下帮助我们用各种方法。
3. Received command to return control to primary controller. 已收到恢复主控制器控制的命令。
英英解释
n.
1. an authoritative direction or instruction to do something
2. a military unit or region under the control of a single officer
3. the power or authority to command
4. availability for use
5. a position of highest authority
6. great skillfulness and knowledge of some subject or activity
7. (computer science) a line of code written as part of a computer program v.
1. be in command of
2. make someone do something
3. demand as one's due
4. look down on
5. exercise authoritative control or power over
