增感屏的增感率是指
A、在照片上产生同等密度05时，无屏与有屏所需照射量之比C
增感屏的增感率定义为：在照片上产生同等密度1.0时，无屏与有屏所需照射量之比
Josephwasverylucky（）withhislife;healmostdidnotgetoutoftheroom.
Imeant____youaboutit,butIforgottodoso.
Ifasubstanceisdissolvedinwaterorheated，itmay（）agas.
Toobtainasatisfactoryresult，onemustapplytwo（）ofpaintonacleansurface.
Heresented_____towait.Heexpectedtheminister_____himatonce.
