单选题The medicine had no ______ on him.

单选题Uniform acceleration occurs ______ the rate of change remains the same over successive and equal intervals of time.

单选题Most people can't ______ the day without at least one cup of tea or coffee. A. get through B. get on C. get at D. get by

单选题 Doctors are to begin a trial of a drug treatment that could double the time transplanted organs survive in the body. The 20-minute procedure effectively coats donor organs in a protective shield that stops them being rejected by the patient's immune system. The treatment is expected to prolong the time that organs remain healthy in patients' bodies and also increase their shelf-life (保存期限), so they can be stored for longer or transported further before being used. If the treatment works, it could ease the burden on organ transplant services, which face an increasing gap between the supply and demand for donor organs. People who receive transplants must take drugs to suppress their immune systems, but the body still reacts enough to cause transplants to fail sooner than they should. A healthy transplanted kidney lasts on average only 10 years, around one third of the time it should last. Organs such as hearts and livers fail even sooner. The consequence is that patients who have had one donor organ often need another. The new treatment, developed by researchers at King's College London, is based on the defense mechanism healthy organs use to shield themselves from immune system. Studies suggest the procedure could extend the life of an implanted kidney by around seven years. The scientists believe the treatment will also extend the shelf-life of donor organs, increasing the time they survive outside the body from no more than 24 hours to several days. This could reduce wastage and double the number of organs that work properly once they are transplanted, doctors said. In early tests, only a fifth of organs worked properly after being stored on ice for 16 hours, compared with 50% of those treated with mirococept (药物：米罗西普). A recent pilot study of the treatment on 16 patients found it was safe to use. Patients who receive donated organs treated with mirococept will still need to take drugs to suppress their immune systems, but doctors said an aim of their research was to see if the use of current drugs, which can increase a patient's risk of cancer, can be reduced.

单选题Migration is usually defined as "permanent or semi-permanent change of residence". However, our concern is with movement between nations, not with internal migration within nations, although such movements often exceed international movements in volume. Today, the motives of people who move short distances are very similar to those of international migrants. Students of human migration speak of "push" and "pull" factors, which influence an individual's decision to move from one place to another. Push factors are associated with the place of origin. A push factor can be as simple and mild a matter as difficulty in finding a suitable job, or as traumatic as war, or severe famine. Obviously, refugees who leave their homes with guns pointed at their heads are motivated almost entirely by push factors (although pull factors do influence their choice of destination). Pull factors are those associated with the place of destination. Most often these are economic, such as better job opportunities or the availability of good land to farm. In general, pull factors add up to an apparently better chance for a good life and material well-being than is offered by the place of origin. When there is a choice between several attractive potential destinations, the deciding factor might be a non-economic consideration such as the presence of relatives, friends, or at least fellow countrymen already established in the new place who are willing to help the newcomers settle in. Besides push and pull factors, there are what the sociologists call "intervening obstacles." Even if push and (or) pull factors are very strong they still may be outweighed by intervening obstacles, such as the distance of the move, the trouble and cost of moving, the difficulty of entering the new country, and the problems likely to be encountered on arrival. The decision to move is also influenced by "personal factors" of the potential migrant. The prospect of packing up everything and moving to a new and perhaps very strange environment may appear interesting and challenging to an unmarried young man and appallingly difficult to a slightly older man with a wife and small kids. Similarly, the need to learn a new language and customs may excite one person and frighten another. Regardless of why people move, migration of large numbers of people causes conflict. The United States and other western countries have experienced adjustment problems with each new wave of immigrants. It has usually taken several decades for each group to be accepted into the mainstream of society in the host country.

单选题Because of her dual nationality in the United States and Mexico, Maria was almost required to pay taxes in both countries until her accountant ______ with a satisfactory solution for both countries.

单选题Born of the same parents, he beam no ______ his brothers.

单选题 筷子 几千年来，我们中国人一直将筷子视为一种将饭送入口中的最简单、有效的工具。早在周朝时期，筷子便被人们用来夹取荤、蔬菜，而米饭在那时则用手来取食。筷子的大小基本一样，而制作筷子的材料则各有不同，所选材料有竹子、木材、玉石等。中国人使用筷子的方法很有艺术性，各人有各人的方法，就好像签名一样，不尽一致。中国人一般都能随心所欲地用筷子夹起一粒米饭，一粒豌豆，甚至一只滑溜溜的丸子。

单选题A: Have you heard that all flights have been cancelled because of the weather? B: ______.

单选题Staples( in the third paragraph) are commodities ______.

单选题(It is) (extremely) important (for) an engineer (to know) to use a computer.

单选题Where do cars get their energy from? For most cars，the answer is petrol.21___________some cars use electricity.These cars have 22 __________motors that get their power from large batteries.In 23 ，ther

单选题Most visitors to that peninsula find the breathtaking scenery, which features the sea and rocks, a great ______. A. threat B. thrill C. thriving D. thrift

单选题______ for several times, Bill made up his mind not to play computer games at night any more.

单选题 He' s a great player and I have a lot of respect_______him.

单选题 Which of the following prepositional phrases can function as an adverbial?

单选题Because of adverse weather conditions, the travelers stopped to camp.

单选题A desert is probably ______.

单选题______ he was aware of the real meaning of life.