Which country is the biggest consumer of petroleum

A．Radars that can help drivers to see obstacles in fog．
B．Devices that can help drivers to see through big vehicles．
C．Improvements in seat helts，pedal controls and tyres．
D．Windscreens that can help drivers to improve their vision．

A．it is natural for teenagers to stay up late and get up late
B．staying up late has a bad effect on teenagers’ability to think and learn
C．during puberty most teenagers experience a kind of gray cloud
D．it is hard for teenagers to get out of bed in the morning