This is a street crossing. There are red and green lights at each corner. Drivers must watch the lights carefully. When there is a green light, the cars may go. When there is a red light, the cars must stop. They must wait until the red light changes to green. Then they can go on. Sometimes the cars want to make a right turn or a left turn. They can make a right turn when the light is green or red. But they must wait until the green light is shining if they want to turn left. Some people are color-blind(色盲). They can not tell the difference(不同) between the red and green lights. These people must not drive, or there will be accidents. We must keep our streets safe. 小题1:Drivers must watch _____ carefully at each corner. A.green lights         B.red lights            C.both green lights and red lights 小题2:When there is a red light _____ . A.the cars must stop                B.the cars may go on      C.the cars may make a left turn 小题3:Cars can make a right turn when _____ . A.there is a red light              B.there is a green light     C.there is a red or green light 小题4:Color-blind people may have accidents because _____ . A.they can’t see cars B.they can’t see the lights C.they can’t tell the difference between the red and green lights 小题5:According to (根据) the passage _____ must not drive. A.young people     B. color-blind people             C.old men