A.对
B.错
[单选题]A.5%B.10%C.15%D.20%E.25%
[判断题]A.对B.错
[单选题]A.栅比B.栅焦距C.栅密度D.铅容积E.聚焦栅距离界限
[单选题]A.2x+lB.2xy+lC.D.