英语虚拟语气It is essential that everyone (should) be prepared for

关于虚拟语气:it is strange that .should +动词原形. It is absolutely essential that 怎么看出是虚拟语气啊 It is essential that everyone ___ what to do. 英语翻译21.It is essential that effective actions should be take 虚拟语气It is high time that we should take effective measures还是 It is stange that he should pass the exam是虚拟语气吗? 在主语从句中it is+adj+that后不是加虚拟语气should+动词原形 it is necessary that后面要用虚拟语气吗?（即加should do）. It is strange that he (should) have made a mistake.如果是虚拟语气sh it is essential that computer security professionals should（ 英语虚拟语气"it is time." it is high time that 是虚拟语气,后面可加过去时或should do,那是不是所有虚拟语气后都可以加