Among the rings of a piston the （） one is subjected to the greatest load and temperature.

A . compression pressure in the cylinder will be higher B . carbon will accumulate behind the ring C . combustion gases will penetrate beneath the ring land D . piston side thrust will be increased

A . seal the space between the piston and liner B . transmit heat from the piston to the cylinder liner C . reduce the amount of combustion gas blow-by D . all of the above

A . prevent an internal explosion in the pump when it is overheated B . enable a visual inspection of the pump while it is running C . insure a proper alignment of the pump coupling to the driver D . accommodate for friction between the impeller and the easing

A . Ⅰ only B . Ⅱ only C . both Ⅰ and Ⅱ D . neither Ⅰ nor Ⅱ

A . Low viscosity index B . Low carbon forming tendencies C . High film strength D . High non-corrosive qualitie

A . Absorb erosion of high velocity discharge stream B . Seal pump shaft against entry of air C . Isolate the discharge side from the suction side D . Dampen the turbulent discharge flow

A . larger than B . smaller than C . equal to D . none of the above

A . becket B . loop C . swivel D . eye

A . provide a reservoir for cylinder lubrication B . pump oil into the combustion space for cylinder cooling C . prevent excessive lubricating oil consumption D . allow hydraulic oil film formation on the cylinder

A . play a great part on B . run a role in C . plays an important part in D . acts as important part at

A . Control the amount of lube oil burned in the combustion chamber B . Transmit heat from the piston to the cylinder liner C . Prevent damage to ring groove inserts by acting as a heat dam D . Dissipate combustion chamber gas pressure by channeling it through the ring ga

A . combustion gas blow-by B . excessive lubrication C . properly functioning rings D . insufficient cylinder cooling

A . insufficient lubrication B . improper piston cooling C . blow-by D . overload operatio

A . (1), (2) and (3) B . (1), (2) and (4) C . (2), (3) and (4) D . None of the above

A、clockwise, due to the bowl rotating clockwise B、clockwise, due to the bowl rotating counterclockwise; C、counterclockwise, due to the bowl rotating clockwise D、counterclockwise, due to the bowl rotating counterclockwise

A、true directions B、compass error C、deviation D、magnetic directions

A . a coil spring B . a sealing ring C . an oil distributor ring D . main seal ring

A．make off B．make up C．make out D．make over

Sure, some leftish billionaires like George Soros have been railing against income inequality for years. But increasingly, centrist and right-wing billionaires are starting to worry about income inequality and the fate of the middle class. In December, Mortimer Zuckerman wrote a column in U. S. News & World Report, which he owns. “Our nation’s core bargain with the middle class is disintegrating, ”lamented （哀叹） the 117th-richest man in America. “Most of our economic gains have gone to people at the very top of the income ladder. Average income for a household of people of working age, by contrast, has fallen five years in a row. ” He noted that “Tens of millions of Americans live in fear that a major health problem can reduce them to bankruptcy. ” Wilbur Ross Jr. has echoed Zuckerman’s anger over the bitter struggles faced by middle-class Americans. “It’s an outrage that any American’s life expectancy should be shortened simply because the company they worked for went bankrupt and ended health-care coverage,” said the former chairman of the International Steel Group. What’s happening？ The very rich are just as trendy as you and I, and can be so when it comes to politics and policy. Given the recent change of control in Congress, the popularity of measures like increasing the minimum wage, and efforts by California’s governor to offer universal health care, these guys don’t need their own personal weathermen to know which way the wind blows. It’s possible that plutocrats（有钱有势的人）are expressing solidarity with the struggling middle class as part of an effort to insulate themselves from confiscatory（没收性的）tax policies. But the prospect that income inequality will lead to higher taxes on the wealthy doesn’t keep plutocrats up at night. They can live with that. No, what they fear was that the political challenges of sustaining support for global economic integration will be more difficult in the United States because of what has happened to the distribution of income and economic insecurity. In other words, if middle-class Americans continue to struggle financially as the ultrawealthy grow ever wealthier, it will be increasingly difficult to maintain political support for the free flow of goods, services, and capital across borders. And when the United States places obstacles in the way of foreign investors and foreign goods, it’s likely to encourage reciprocal action abroad. For people who buy and sell companies, or who allocate capital to markets all around the world, that’s the real nightmare. 第57题：What is the current topic of common interest among the very rich in America？ A．The fate of the ultrawealthy people. B．The disintegration of the middle class. C．The inequality in the distribution of wealth. D．The conflict between the left and the right wing