取得保密资格的单位都应当被列入《武器装备科研生产单位保密资格名录》。（）
参考答案：对
Mary and Rose _____ friends since they met in London in 1998.[ ]
A. have made
B. have been
C. made
D. have become
酶分子的物理修饰有什么作用？
