A．凸镜用于汽车头灯
B．凹镜用于太阳灶
C．凹镜可用作观后镜
D．凹镜用于放大镜
答案：B
(2013·安徽省芜湖三校一模)A recent study has found that the number of smokers ________ sharply over the past five years.
A．is increasing
B．are increasing
C．has been increasing
D．have been increasing
下边漫画《吃得苦中苦，方为人上人》主要告诉我们[ ]
A．要大力发扬艰苦奋斗精神
B．要大力发扬团队精神
C．要大力发扬创新精神
D．要树立终身学习的观念
