command
1.command语气很强，如说上级“命令”下级。父母叫子女做什么事该用tell，不用command。
2.in command of是“统率…的”，under the command of是“被…所统率的”，如General Johnson was in command of the army和The army was under the command of General Johnson。under the command of里的the偶尔省去。
3.a good command of English里的command指“应用能力”，不指“知识”。
4.get command of, obtain command of和assume command of等表达方式里在command前面习惯没有the。
5.command不论用作名词或动词，后面的以that引导的从句里习惯用should或虚拟现在式，如He issued a command that each of them (should) come at eight o'clock和He commanded that each of them (should) come at eight o'clock。
