Which of the following devices is a common basic element with nearly all mechanical governors?

A．Power piston

B．Control rack

C．Weights acted on by centrifugal force

D．Isochronous（同步的）droop spring

[单选题]Which of the following devices is a common basic element with nearly all mechanical governors?（）A . Power pistonB . Control rackC . Weights acted on by centrifugal forceD . Isochronous droop spring

[单选题]Which of the following devices is common to both mechanical and hydraulic governors?（）A . Direct linkage between the ball-head and fuel rackB . A servomotorC . A compensating deviceD . Flyweight

[单选题]Which devices are instruments of interpretation and communication between humans and computers?A．main memoryB．input/output devicesC．CPUD．hard disk

[单选题]Which of the listed devices may be used as a digital device?A．variable resistorB．diodeC．strain gaugeD．thermistor

[单选题]Which of the following is NOT mentioned？A．Supermarket. B.Police station. C.School.

[单选题]In a computer，which of the following is the longest period? (66) .(66) A．Beat periodB．Machine periodC．Instruction periodD．CPU period

[单选题]Which of the following information is NoTmedtioned？A．Who wrote the stories. B.Which story is the longest.C．When we added the stories. D.Who added the stories.

[单选题]Which of the following is the result of the volcanic eruption?A． People stop traveling in EuropeB． Airlines suffer from the loss of planesC． It becomes dangerous for animals to eat outsideD． Farmers have lost many of their animals

[单选题]Which of the following statements is NOT true?A．) World population is increasing at a rate of 150 per minute.B．) Lower death rates also contribute to world population growth.C．) The population of Columbia has been doubling every year for 21 years.D．)

[单选题]Which of the following statements is NOT true?A．Sir Ludwig Guttmann is an early organizer of the games for the disabled.B．Sir Ludwig Guttmann is an injured soldier.C．Sir Ludwig Guttmann is from Germany.D．Sir Ludwig Guttmann is welcomed by the British