Driving cars, trucks and motorcycles is an important part of our lives. We do it every day

Driving can be very convenient, but can also cause many problems. Waiting in line at a red light, a driver may get impatient and decide just to drive right through it. If another car is coming from the other direction, there might be a terrible accident. Cutting another car off can make its driver angry, so that driver cuts off someone else. Pretty soon everybody is angry, and impatient.

Traffic accidents declare millions of lives every year worldwide. In America alone, over seven people are killed in accidents every day. The annual death rate (年死亡率) from traffic accidents in America is twice that of Japan. To allow traffic to move smoothly and safely, everybody must follow the rules. Before you drive, learn all the traffic laws. That way of driving is safe, convenient and even fun!

The word "convenient" in the passage means ______.

A．handy, easy to do

B．that can be changed

C．fond of drinking and merry-making

D．carriages or other trucks