【简答题】上证成分股指数和上证A股指数都采用派许加权综合价格指数公式计算。( )
【单选题】We don’t know the news _____ we will have a test tomorrow. A. that B. if C. whether D. how
【简答题】We don’t know if the plan will work until we ________.(practice)
【判断题】If we don’t know the fact that the same word means differently in different contexts, communications will be hindered.A. √ B. ╳
【单选题】If we don’t know the receiver’s name, wo often use ________ in business letters.