【判断题】A preview statement is usually necessary in the introduction even when a speaker is addressing an audience that is well-informed about the topic.
【简答题】What is a preview statement?
【单选题】药物不良反应的副作用是
E.
当-种药物具有多种药理作用时,除治疗作用之外的其他不利作用
【判断题】What is a preview statement? Preview statement is a statement that indicates when the speaker has finished one thought and is moving on to another.
【判断题】判断一个集合是向量空间需要验证:集合是一个非空集合以及集合对于加法运算和数乘运算具有封闭性。