题干
.
He spent more than twice as much time on the problem _____ I spent on it .
He spent more than twice as much time on the problem _____ I spent on it .
A： tha
B：a
C：le
D：so
答案(点此获取答案解析）
B
)组成，棱镜的横截面如图12－1－14所示．一平行于横截面的光线从O点垂直AB边射入棱镜，先后经过AC边和CB边反射后，从AB边的O′点射出，则出射光线是( )
