单选题Which of the following operations may be dangerous?

单选题They have developed techniques: which are ______ to those used in most factories. A. simpler B. better C. superior D. greater

单选题What they have in common is that they have a high object in life．

单选题They kept on trying their best to develop their business, but in such intense market com- petition, they had no idea if success would come along one day.A)他们努力地发展着自己的事业，但是在如此激烈的市场竞争中，成功是否会在一天来到，他们不知道。B)他们虽然努力恪守着发展事业的想法，但在如此竞争激烈的市场中，他们抱着并不在乎成功是否到来的信念。C)他们一直努力地发展着自己的事业，但是在如此激烈的市场竞争中，他们真不知道是否有一天成功会来临。D)他们不断地努力，发展着自己的事业，但在竞争如此激烈的市场中，对于成功与否他们并没有把握。

单选题______another chance, I will certainly pass the driving test.A) GiveB) To giveC) GivingD) Given

单选题As far as I'm concerned, I don't like ______ in that way. A. to be treated B. to treat C. treated D. treating

单选题______ of the villagers knew the news because it was kept secret. A. Each B. Anyone C. No one D. None

单选题The doctor recommended that he______a rest for a few days．

单选题After ordering the goods, Mr. Smith might pay for them within two weeks because ______. A) the furniture is 25% lower in cost C) he can enjoy 2% discount B) the product may be out of stock D) he can get them within 30 days

单选题If you hide behind the cubes during an attack you can ______.

单选题There are no less than 3,000 students ______ Chinese here.A. studyB. to studyC. studiedD. studying

单选题We are confident to overcome diflfjcuries since the government has agreed to give us some help．A) 既然政府答应给予帮助，我们就有信心克服困难。B) 自从政府答应给予帮助以来，我们就有信心克服困难。C) 我们都在等政府给予帮助以渡过危机。D) 因为政府答应给我们一些帮助，我们就有信心克服困难。

单选题His teacher ______ concern about the progress he had made at school. A. expressed B. exported C. exploded D. exposed

单选题Young people now live a life-style ______ their parents could hardly dream of.

单选题The periods of fever tend to occur at regular intervals with relative freedom from symptoms between. A．发烧往往在一定间隔后出现，而在此间，症状相对消失。 B．发热期往往以一定的间隔出现，在两次发热期间，相对来说没有症状。 C．这些阶段性的发烧有可能会定期发生，而在此之前，征兆会相对减轻。 D．这阶段的发烧发生在有一定间隔但又相对没有症状的自由人群中间。

单选题It"s always a good idea to put on your seat belt when you"re in a car. Why? Think about this example: You put an egg on a skateboard (滑板) and give it a push. If the skateboard hits a stone, it will stop, but the egg won"t. It will fly through the air, hit the ground, and break. Now, think what would happen if you tied the egg to the skateboard. When the skateboard hits a stone, the egg won"t go flying. It will stay safely on the skateboard. Volvo, a famous Swedish carmaker, was the first to use seat belts in 1949. Air bags are also very important for car safety because sometimes a seat belt isn"t enough. If the car is going really fast and runs into something, seat belts could even hurt the people who wear them. Most newer cars have air bags in front of and next to the seats. When a car hits something, its airbags will come out quickly in less than one second—to keep the people inside safe.

单选题Her ability has been doubtful after a number of_________.

单选题Take the umbrella with you______it rains.

单选题In everyday usage "hot" means "having a lot of heat". Many people think that "cold" is something completely separated from heat. But this is not true. "Cold" simply means "having little heat". Your life depends on heat. In fact, every living thing depends on it. Without heat, every living thing would be frozen to death. All living things get their heat from the sun, which provides the conditions in which life is possible. Since before the dawn of history, man has been able to make his own heat. He has been able to release the sun"s heat that is trapped in things such as wood, coal, and oil. And he has been able to use this heat. Heat has made civilization possible. With heat, man could melt metals. As man learned to use metals and fuels, industries grew. As a result, engines were invented. These are machines that change heat energy into mechanical energy. Engine can do the work of many men. Without engines industrial civilization is impossible. Yet when the first engines were built in the 17th century, men were still wondering about the nature of heat. "What is it?" they asked. Not until the early years of the 19th century did they find the right answer.

单选题So many representatives ______ , the conference had to be put off.