沉降剂（聚丙烯酰胺）的特性有（）
A、絮凝性
B、粘合性
C、降阻性
D、可燃性
E、增稠性
参考答案：A, B, C, E
— What do you think of your new English teacher?
— She was well prepared for her first lesson and left us a good ______. [ ]
A. expression
B. instruction
C. appearance
D. impression
在常值变量中，整型的最大值是【 】。
