亚临界、超临界和超超临界全部是按（）来划分的。
A.温度
B.压力
C.温度和压力
参考答案：B
已知点A（3，1）和点B（4，6）分别在直线3x-2y+a=0两侧，则a的取值范围是[ ]
A、a＜-7或a＞0
B、a=7或a=0
C、-7＜a＜0
D、0＜a＜7
— Bob! How is your project? I heard you started it last Friday, right?
— Oh! I_____ for it. But I haven't decided when to do it. [ ]
A. have prepared
B. had prepared
C. have been preparing
D. was preparing
