什么是 imperative sentences

什么是imperative tense 什么是 imperative sentences imperative imperative 为什么是It is imperative that this mission not fail.而不是It is imperative that this mission don't fail. imperative是什么意思 imperative是什么意思 imperative是什么意思 imperative是什么意思 imperative是什么意思 imperative是什么意思 imperative style 英语It is imperative that this mission not fail为什么是It is imperative that this mission not fail.而不是It is imperative that this mission don't fail. it is imperative that? strategic imperative什么意思 categorical imperative是什么意思 imperative是什么意思?instructed是什么意思? THE ROMANTIC IMPERATIVE怎么样