题目

利用下列各组物质制备和收集相应的气体，适宜采用下图所示装置的是（    ） ①电石和水  ②MnO2和浓盐酸  ③Cu和稀硝酸  ④Na2SO3和硫酸  ⑤浓盐酸和浓硫酸                               A.②③                     B.④⑤                      C.①⑤                      D.①④句型转换 I have learned about 20 English songs this term. (对加粗部分提问) How ________ English songs have you learned this term?