单项选择题
A．They are entertaining. B．They are time-consuming. C．They are boring. D．They are rewarding.
A．8 years. B．16 years. C．20 years. D．30 years.
A．It can measure the driver’s alcohol level in the blood. B．It bases its analysis on the driver’s heartbeat. C．It can quicken the driver’s response to emergencies. D．It monitors the signals transmitted from the driver’s brain.