减少和排除散射线的方法中,下列哪项错误()
A.缩小照射野
B.用金属后背盖的暗盒
C.用遮线筒或缩光器来
D.选择高电压摄影的方法
E.使用滤线栅
参考答案:D
小明看一本书,看了40%后,还剩下54页,这本书共有多少页?
The two naughty boys were quiet when eating, and they were accustomed to ______ at meals.
A.talk
B.talking
C.not to talk
D.not talking