铁水预处理脱硫剂（）扒渣容易。
A.石灰
B.苏打
C.电石
D.金属镁
参考答案：A, C
交互图标具有显示图标和判断图标的功能，其交互效果有（）。
A.目标区
B.动作
C.按钮
D.文本输入
His first book is of great use for our course. But his latest one is ____ worth reading.
A. better B more C. much D. very
