目前全世界致盲的最主要原因是（）
A.老年性黄斑变性
B.沙眼
C.白内障
D.糖尿病性视网膜病变
E.青光眼
参考答案：C
—What about your self-drive trip yesterday?
—Tiring! The road is being widened, and we ______ a rough ride.
A．had
B．have
C．would have
D．have had
石油起火最佳灭火剂是泡沫，因为它能均匀的逐渐的覆盖在油面上，使火熄灭。
