第22题: [单项选择]This is a very difficult operation. It is essential that you ______ for emergency. A. are to be prepared B. would prepare C. be prepared D. must be prepared 参考答案:C 答案解析:[解析] 考查知识点:虚拟语气的用法。在It is essential引导的从句中,谓语动词应该用should+动词原形,should可以省略。译文:这个手术很难,你有必要做好应付紧急情况的准备。