单项选择题
From the story at the beginning of the passage we know it is dangerous for a driver（）
A．to see red traffic lights B．not to notice the traffic lights C．to be color blind D．not to see the red traffic lights
单项选择题 21（）
填空题 A．large B．orange C．singer D．vegetable
单项选择题 What______ doing when you______
