k线中的四个价格中，最重要的价格是（）
A.开盘价
B.收盘价
C.最低价
D.最高价
参考答案：B
用所给单词的适当形式完成短文。
Yesterday Grandma 1._____ (cook) fish Amy 2._____ (help) her mother. Grandp3._____ (walk) in
the park. Sam 4._____ (play) on the computer. Tom 5._____ (play) with his toys. Their father 6._____
(watch) TV. They 7._____ (be) very happy.
被大量钙、镁离子污染的玻璃器皿可用下列哪种洗涤剂洗涤（）
A.合成洗涤剂
B.铬酸洗液
C.尿素洗液
D.EDTA-Na2
