下面四种混砂机，（）混砂机的轮子对型砂没有搓研作用。
A.碾轮式
B.碾轮－转子式
C.摆轮式
D.连续式
参考答案：C
He has got used to the surroundings and now he is getting on well with his classmates. __________, he has _________ the life in high school.
A．At all; adjusted to
B．All in all; adapted to
C．After all; fitted
D．In al; been suitable for;
无土栽培的固体基质要求（）。
A.无毒
B.透气
C.疏松
D.排水良好
E.有机质含量高
