单项选择题
A．Put up your hands. B．Don't move or I'll shoot you. C．If you want to have lunch, you must listen to me. D．You go first slowly and we'll have lunch together.
A．Henry Ford always tried to avoid waste B．Henry Ford required total observation once the standards were established C．Henry Ford always encouraged his workers to make changes oft he products D．Henry Ford made his own designs of his cars
A．it is one thousand times more precise than microwave radar B．it provides precise measures of the velocity of space vehicles C．it is a new system of radar D．it can measure the movement of a spaceship less accurately than a microwave radar