第2题: [单项选择]It is (necessary) that the (customs) (of all) nations (must be respected). A. necessary B. customs C. of all D. must be respected 参考答案:D 答案解析:虚拟语气用法错误,应改为(should)be respected。在让it is necessary/important that... (做…是必要的/重要的)句型中,要用虚拟语气,其构成是shou