The presence of bubbles in a refrigeration system liquid line may （）.

A . auto-ignition point B . flash point C . burning temperature D . fire point

A . center of gravity B . metacenter C . center of flotation D . keel

A、oxygenating B、oxidizing C、deoxygenating D、proportioning

A . submerged hulls B . quarters C . columns and upper structure D . submerged connecting structure

A . boiling point B . flash point C . viscosity point D . toxic point

A . fuel valves of main engine B . injector pump of main engine C . safety valves of marine boiler D . safety valves of a reciprocating pum

A . heavy rain B . heavy snow C . thick fog D . clearing skie

A . as long as B . unless C . despite D . till

A . flash point B . upper explosive limit C . lower explosive limit D . fire point

A . tightened up B . sealed up C . opened up D . unscrewed

A . flash point B . fire point C . upper explosive limit D . lower explosive limit

A . Proper refrigerant charge B . Faulty expansion valve C . Insufficient refrigerant D . Solenoid valve stuck ope

A . east iron is a cheap material B . cast iron can pollute sea water C . cast iron has mere corrosive than bronzes to sea water D . cast iron is more corrosive to sea water when it meets with bronze

A . sound the danger signal B . when taking action, make only course changes C . avoid altering course toward a vessel abaft the beam D . All of the above

A . too much refrigerant in the system B . oil entrained in the refrigerant C . less than a full charge of refrigerant in the system D . ice crystals forming in the refrigerant

是 否

A．To explain why some paints may deteriorate over the course of time B．To stress the need for caution when attempting to restore old artworks C．To show how pigments differ from varnishes and binding agents D．To show how spectroscopy can help establish the age of a painting 此题为多项选择题。

M: Me too. Take it easy. I consider it a natural human response. You just need time and practice. Practice makes perfect. Q: What does the man mean？ (17) A．She should follow the human nature. B．Strangers are nothing to be afraid of. C．Feeling nervous is nothing improper. D．She should accept strangers' presents naturally.

The【B10】of this music are as interesting as the music【B11】. American Negroes, or blacks, as they are called today, were the jazz【B12】. They were brought to the Southern states【B13】slaves. They were sold to plantation owners and forced to work long【B14】. When a Negro died his friends and relatives【B15】a procession to carry the body to the cemetery. In New Orleans, a band often accompanied the【B16】. On the way to the cemetery the band played slow, solemn music suited to the occasion. 【B17】on the way home the mood changed. Spirit lifted. Death had removed one of their【B18】, but the living were glad to be alive. The band played【B19】music, improvising on both the harmony and the melody of the tunes【B20】at the funeral. This music made everyone want to dance. It was an early form. of jazz. 【B1】 A．At B．In C．By D．On

In the 1980's, real estate prices soared to super inflated levels, and investors sank their money into the booming stock market. There seemed to be no end in sight for the land of the rising sun. Everything was rising, and the government, financial institutions, and individuals paid little heed to the warning signs of an imminent crash. Then, the bubble burst, and land and stock prices plunged. What is the result of the crash？ Many companies have faltered due to poor sales and bad debt, and have closed their doors. The domino effect on many financial institutions is that they must- bear an enormous number of unrecoverable loads, which have resulted when companies, depending on profits from land in vestments to repay loans, have fund themselves insolvent. Furthermore, many individual depositors, fearing a collapse of more banks and securities companies, have withdrawn their money in droves. Attempts by tile government to revitalize the sluggish and contracting economy have proven fruitless. Pump-priming measures including tax cuts and public works spending have done little to put the economy on tract again. What's more, the government's decision to increase the consumption tax from 3 to 5 percent in 1997 has had a devastating impact on consumer spending. As for the business sector, companies have tried various measures to streamline management, but other ill effects of such policies, including rising unemployment among older workers, have surfaced and have dealt a huge blow to the recovery process, Japan' s faltering economy has had an impact on other Asian countries, and some fear that the whole region will be drawn into depression. What will stem the tide of further economic collapse？ For one, Japan must stabilize its financial system and take immediate and effective measures to deal with non – performing loans. Revealing the severity of the problem to the public and foreign governments is an essential first step. A more vital solution might be to institute a permanent tax cut to stimulate consumer spending and confidence in the government' s handling of the situation. Ultimately, this will encourage domestic demand for goods and services and will be the driving force behind much of the recovery, That' s the bottom line. Of course, many more factors including deregulation will play a vital role in expediting economic stabilization and growth. Whatever the case, action must be carried out swiftly and decisively. A passive and .reticent approach to reform. and change is what has hampered any improvement so far. Other nations have encouraged Japan to step up the pace of implementing change, but Japan must make the first step . . . or else we might be witnessing the setting of this great rising sun. Japan's current economic crisis is the worst since ______. A．World War Ⅰ B．World War Ⅱ C．the Gulf War D．the Korean War

Many researchers believe that the presence of RNA in brain cells is the biochemical basis of memory; that is, the presence of RNA enables us to remember. Because certain chemicals are known to inhibit the synthesis of RNA in the body, we can test this hypothesis. Animals that have learned particular responses can be injected with an RNA inhibitor and then tested for memory of the learned responses. Which of the following test results would most seriously weaken the case for RNA as the basis of memory？ A．After an injection of RNA inhibitor, a wide range of behaviors in addition to the learned responses were affected. B．After an injection of RNA inhibitor, animals that had not consistently been giving the learned responses were able to give them consistently. C．After injections of RNA inhibitor, some animals lost memory of the learned responses totally but others lost it only partially. D．After a small injection of RNA inhibitor, animals responded well, but as the size of the injection increased, they gave fewer of the learned responses. E．After an injection of RNA inhibitor, animals could not learn a new response.

A．BCL-2 B．p53 C．NF- kappaB D．Cytochrome P-450 E．Granzyme B