(A) Malcolm sits by the window.(B) Malcolm lives in New York (C) Elsa lives in Florida.(D) Elsa changed her seat because a man next to her was smoking.(E) Elsa’’s boyfriend and she still live near Spaceport.(F) Malcolm still lives a few miles from Spaceport.(G) Malcolm sold the house and the furniture a few miles from Spaceport and moved to his friend’’s in Florida.(H) Malcolm has move to New York.

X线照片上某处阻挡光线能力的大小称为

A．亮度

B．密度

C．对比度

D．透光率

E．阻光率