创造性又被称为（）。
A.显而易见性
B.显著性
C.先进性
D.进步性
参考答案：C, D
As students, we are supposed to _______ more time _______. [ ]
A. spend, studying
B. take, to study
C. spend, play computer games
D. take, to watch TV
氢冷系统氢气纯度应不低于96％，氧气纯度应不大于2％。
