[单项选择]

Inertial guidance is the name given to those types of systems which guide and keep track of the location of vehicles which are free to move in three dimensions. Vehicles which move only on a plane surface, such as ships or automobiles, require only an accurate compass, sextant, and clock to keep track of their present position. When a vehicle can travel up or down as well as north or east, it is much more difficult to fix its position. An inertial platform is used in inertial guidance to measure vehicle altitude and acceleration which are then integrated to provide position and velocity. The inertial platform consists of three gyroscopes and three accelerometers mounted in the inner gimbal of the four gimbal platform. The purpose of the inertial platform is to allow the vehicle to move in any direction about the inner gimbal containing the gyros and accelerometers, without disturbing or turning them from their original orientation. Thus the gyros and accelerometers do not mm when
A. space in three dimensions.
B. poor visibility and meteorological conditions.
C. the altitude and position of a vehicle.
D. spacecraft productivity.

[单项选择]

Inertial guidance is the name given to those types of systems which guide and keep track of the location of vehicles which are free to move in three dimensions. Vehicles which move only on a plane surface, such as ships or automobiles, require only an accurate compass, sextant, and clock to keep track of their present position. When a vehicle can travel up or down as well as north or east, it is much more difficult to fix its position. An inertial platform is used in inertial guidance to measure vehicle altitude and acceleration which are then integrated to provide position and velocity. The inertial platform consists of three gyroscopes and three accelerometers mounted in the inner gimbal of the four gimbal platform. The purpose of the inertial platform is to allow the vehicle to move in any direction about the inner gimbal containing the gyros and accelerometers, without disturbing or turning them from their original orientation. Thus the gyros and accelerometers do not mm when
A. to prevent the ship or plane from moving off course.
B. to send information from the ground control unit.
C. to maintain the speed of the ship or plane.
D. to prevent a change in the systems orientation.

[单项选择]The examples given of types of classified advertisement are mentioned EXCEPT ______.


A. houses for sale
B. people who are asking for help
C. something that has been lost
D. job vacancies

[单项选择]One of the examples given of types of classified advertisement is ______.


A. houses for sale
B. people who are asking for help
C. people who are lost
D. rare objects

[单项选择]Financial aid is largely given to those who ______


A. study well.
B. need money.
C. cannot repay.
D. lose their jobs.

[单项选择]There are two types of employees: Those who do the work and those who take the credit. Try to be in the first group; there is much ______ competition there.


A. more
B. less
C. little
D. few