世界上最著名的两种科学杂志是（）和Science。
A.Nature
B.Economic Review
C.AGRICOLA
D.IEL
参考答案：A
Professor Lee failed many times but he ________found a good way to solve the problem.
A．gradually
B．entirely
C．finally
D．frequently
粒径在100v以下
A．流动性良好B．粒子间内聚力和摩擦力开始增加C．粒子易发生聚集D．空隙率大E．粒子不流动
