If a substance is dissolved in water or heated, it may-______ a gas.

A . chemical ignition B . spontaneous combustion C . chemical combustion D . radiation ignitio

A . Impurities B . Lube oil C . Gasoline D . Diesel fuel

A . A. To make a wound smooth. B . B. To prevent disease entering a wound. C . C. To cover a rough surface. D . D. To help a wound to dry.

A .  It can never be used for a restore/recover operation. B .  Oracle will remove the backup set pieces from the flash recovery area. C .  The backup has been used at least once to restore and recover the database. D .  The backup is no longer valid because of a resetlogs operation. E .  The physical backup set pieces are missing from the media.

A . fusion B . vaporization C . condensation D . sublimatio

A . carbon B . vanadium C . calcium D . hydroge

A . Refrigerator B . Refrigerant C . Cooling medium D . Brine

A . explosive range B . flash point C . ignition temperature D . combustion temperature

A . polluter B . emitter C . spiller D . oiler

从表面上看，许多婚姻似乎是因为有了“第三者”才破裂的。然而这只是一种心理幻觉。那个女人，或者那个男人，实际上掩盖了一个已经失却真正意义的婚姻的解体。

Its effects are ___16___ those of cocaine and heroin. "No Tobacco Day" is intended for smokers and ___17___ who earn money from tobacco sales. So businesses are urged to stop selling tobacco products for twenty-four hours. ___18___ are urged not to carry advertisements for cigarettes. WHO has approved plans to help reach its ___19___ of a "smoke-free" world. They urge governments to take action to help ___20___ make money by growing other crops. They also call for improved public information campaigns about the risks of smoking. 11题选() A.whether B.which C.when D.what 12题选()A.to chew B.chew C.chewing D.chewed 13题选()A.problems B.questions C.results D.behaviors 15题选()A.difficult B.inconvenient C.worrying D.reasonable 18题选()A.Readers B.Books C.Managers D.Newspapers 20题选()A.Workers B.manufacturers C.farmers D.producers 19题选()A.Objet B.goal C.destination D.direction 14题选()A.at beat B.at most C.at worse D.at least 17题选()A.that B.this C.these D.those 16题选()A.better than B.similar to C.consistent with D.dependent on 请帮忙给出每个问题的正确答案和分析，谢谢！

Using placebos to test drugs sometimes has a surprising result. Researchers say people taking the placebo often report improvements in their health. This is known as "the placebo effect"--pain that is eased or stopped by an inactive substance. In such testing, the drug must perform. better than the placebo to prove that it is effective. Doctors have reported that the placebo effect can be used in treatment. For example, a doctor tells a patient that a new drug will stop the pain in his leg. The pill is only sugar. But the patient does not know that. He takes the pill and says his pain is gone. Scientists are beginning to discover some physical reasons for this reaction in some people. They are learning that much of what people believe to be true comes from what the brain expects is going to happen. If the brain believes a drug will ease pain, the brain may begin physical changes in the body that can cause the expected effect. A recent examination of studies on drugs for depression found that placebos eased the depression about as well as the active drugs. Other studies have explored the power of placebos. A study in Japan involved thirteen people who reacted to the poison ivy (常青藤)plant. Poison-ivy causes red itchy sores(伤痕)on some people who touch it. Each person was rubbed on one arm with a harmless leaf, but was told it was poison ivy. Each person was then touched on the other arm with poison ivy, but was told it was a harmless leaf. All thirteen people developed a reaction on the arm where the harmless leaf touched their skin. Only two reacted to the poison ivy leaves. Doctors and scientists worry that the use of placebos may not always be harmless. They say people can become victims of false doctors and others who use placebos to claim they can cure disease. What do medical researchers usually use to make placebo pills？ A．Ivy leaves. B．Harmless leaves. C．Medicine being tested. D．sugar.

A sample of HgCl₂;weighing 9.41 g is dissolved in 32.75 gethanol (C₂H₅OH). The boiling point elevation of the solution is1.27℃.Is HgCl₂an electrolyte in ethanol？ Show your calculations.(Kb=1.20K·kg·mol^-1)

A、Security prices would react only to the “unexpected” elements of information. B、Investors would prefer active investment strategies to passive investment strategies. C、The time frame for price adjustment allows many traders to earn profits with little risk.

A．product appearance B．the inspection report C．product melting point D．product color

是 否

A．increase B．reduce C．help D．break into small pieces