【简答题】听力原文:Woman: I tried this pair of shoes and I think I like this colour and style. Please pack them. By the way, I notice that all the goods in your shop are at 20% discount. And this price tag says 20 ...
【单选题】关于力和力的投影,下列哪种说法是正确的( )
【判断题】力的投影与力的分量是两个不同的概念。力的投影是代数量,而力的分量是矢量。
【多选题】关于力和力的投影,下列哪些说法是正确的()。