题目

关于平面向量．有下列三个命题： ①若，则． ②若，，则． ③非零向量和满足，则与的夹角为． 其中真命题的个数有（ ）． A．0 B． 1   C ．2   D ．3 答案：B   只有②正确,故选B.根据句意和汉语注释，写出单词的适当形式。1.Your spoken English is so poor, please correct your ___________（发音）.2.His parents have_______________（答应）to buy a new mobile phone for him．3.The manager is strongly against ___________（回复）to that foreign company at once.4.Lu Xun is one of the ___________（先锋）of modern Chinese culture.