______ play a very important part in hydraulic systems by preventing interaction between different parts of the hydraulic circuit.A.MotorsB.Check valvesC.Safety valvesD.Reducing valves
______ play a very important part in hydraulic systems by preventing interaction between different parts of the hydraulic circuit.
A.Motors
B.Check valves
C.Safety valves
D.Reducing valves
相关考题：
_______ exchanges are an important part of cultural exchanges between twocountries. A. previousB. uneasyC. academicD. divine
PART CDirections: You will hear three dialogues or monologues. Before listening to each one, you will have 5 seconds to read each of the questions which accompany it. While listening, answer each question by choosing A, B, C or D. After listening, you will have 10 seconds to check your answer to each question. You will hear each piece ONLY ONCE.听力原文： The piano and violin are girls' instruments. Drums and trumpets are for boys. According to Psychologists Susan O' Neil and Michael Bottome, children have very clear ideas about which musical instruments they should play. They found that despite the best efforts of teachers, these ideas have changed very little over the past decade. They interviewed 153 children, aged between 9 and 11, from schools in northwest England. They asked them to identify four musical instruments and then say which they would like to play most and which they would least like to play. They also asked the children for their views on whether boys or girls should not play any of the four instruments. The piano and violin were both ranked more favorably by girls than by boys, while boys preferred the drums and trumpets. There was a broad agreement between boys and girls on which instruments each sex should play and the reasons varied. And while almost half of all boys said they avoided certain instruments because they were too difficult to play. Only 15 percent of girls gave that as a reason. Earlier studies indicated that very young school children aged between 5 and 7, showed no bias in choosing musical instruments. But their tastes become more clear between the ages of 8 and 10. One survey of 78 teachers suggested that after that age, both boys and girls begin to restrict themselves to the so-called male or female instruments.How many children did Susan and Michael interview?A．150.B．151.C．152.D．153.
6 An important part of managing people in a professional organisation is to be able to distinguish between aggressiveness and assertiveness in an employee.Required:(a) Explain and give examples of aggressive behaviour. (8 marks)
Which of the following is implied in the passage?A．A very important purpose of bank-supervision is to provide adequate capital for their operation.B．A very important purpose of bank-supervision is to ensure banks to operate with adequate capital.C．A very important purpose of bank-supervision is to put additional restrictions on the banks' operations.D．A very important purpose of bank-supervision is to concentrate on risks.
VIP是以下哪组词的翻译A. Very important placeB. Very interesting personC. Very important personD. Very interesting place
Parents play a very important __________ in their children's education. A、classmateB、offerC、ripeD、role
It is very important for us to find a () between work life and home life. A.wayB.balanceC.blank
______ is not usually used in liquid cargo systems．A.Hydraulic drive systemsB.Electric drive systemsC.Steam drive systemsD.Man-powered drive systems
Even though its economy continues to recover,the US is increasingly becoming a nation of part‐timers and temporary workers.This“disposable”work force is the most important（ ）in American business today,and it is fundamentally changing the relationship between people and their jobs.A.approachB.flowC.fashionD.trend
When the students listen to recorded materials there is very little opportunity for immediate interaction.（）
VIP是以下哪组词的翻译。（）A、Very important placeB、Very interesting personC、Very important personD、Very interesting place
单选题What is the text about?AAdvertisements are the most important part in newspapers.BIt introduces newspapers past and today and its contents.CThere is a lot of useful information on newspapers.DPeople like newspapers very much.
单选题Which of the following hydraulic systems is not one of the three sub-division of the Hydraulic drive system?（）AConstant pressure systemBVariable pressure systemCVariable displacement systemDConstant volume system
单选题A reservoir, as used in hydraulic systems aboard ship, is used to store hydraulic oilAnother function is to（）Aact as a shock absorberBmaintain the stored oil under pressureCact as a base or foundation for the power unitDeliminate pressure surges in the system
单选题（） play a very important part in hydraulic systems by preventing interaction between different parts of the hydraulic circuit.AMotorsBCheck valvesCSafety valvesDReducing valve
单选题It is important with all hydraulic systems to ensure that interlocking arrangements provided for pump or motor control levers are （） before the pump driving motor can be started.Ain the pert positionBin the starboard positionCin the neutral positionDto be dismantled
单选题In which of the listed hydraulic systems will the installation of an oil cooler be necessary?（）AConstant tension mooring winch systemBHatch cover systemCWatertight door systemDInternal combustion engine hydraulic starter system
单选题From the passage, we can draw a conclusion that _____.Afamily has deep influence on a personBcompliments are very important to a personCone should treasure the relationship between othersDwhen facing tough time, one should never say die
单选题The film of oil between the rings and the liner is not only essential for the lubrication but also （） achieving a gas seal.Aplay a great part onBrun a role inCplays an important part inDacts as important part at
单选题What can we learn from the passage?AIt may be difficult for the young to learn new skills.BDogs play an important part in language and culture.CWe can be successful if we learn from our own mistakes.DDogs like the hottest days in summer very much.
单选题The author of The Portrait of a Lady is best at _____.Aprobing into the unsearched secret part of human lifeBa truthful delineation of the motives, the impulses, the principles that shape the lives of actual men and womenCdramatizing the collisions between two very different cultural systems on an international sceneDdisclosing the social injustices and evils of a civilized society after the Civil War
单选题If the relief valve on the discharge side of a hydraulic pump lifts, the cause could be （）.Aa low load on the unitBa clogged pump suction strainerCa blockage in the line between the pump and hydraulic motorDthe hydraulic motor turning too fast