下列各种岩石中可能找到生物化石的是 [ ]
A、花岗岩、玄武岩
B、板岩、页岩
C、砾岩、砂岩
D、石灰岩、大理岩
答案：C
The invention of the chip greatly _______ the development of computer science; _____ the computer
science stepped on the freeway of rapid development. [ ]
A. improved; after that
B. advanced; after that
C. quickened; after which
D. advanced; after which
一般顺流再生固定床反洗后排水至树脂层上水面高（）毫米为宜。
A、150~200
B、350~400
C、250~300
D、400~450
