单选题I am sorry I______ your glasses off the desk when I was wiping it.

单选题Corn originated in the New World and thus was not known in Europe until Columbus found it ______ in Cuba. A. being cultivated B. having cultivated C. has been cultivated D. cultivating

单选题______ of them knew about the plan because it was secret. A. Some B. Any C. No one D. None

单选题The Nobel Prizes are awards that are given each year for special things that people or groups ofpeople have achieved. They are awarded in six ____请作答此空______ : physics, chemistry, medicine, literature

单选题I was so________the night before my examination that I could not sleep.

单选题The quality of education in this small school is better than______in some larger schools.

单选题Some biologists argue that each specifically human trait must have arisen gradually and erratically, and that it is therefore difficult to isolate definite ______ in the evolution of species.

单选题The method in which the writer believes is most effective for the poor benefiting from the rich is ______ .

单选题Unlike a judge, who must act alone, a jury discusses a case and then reaches its decision as a group, thus minimizing the effect of ______ bias.

单选题Can you Ucompress/U your speech into five minutes due to limited time for the meeting?

单选题Twenty teenagers are interviewed about the thing they like best, and 80 per cent named TV without ______.

单选题There are no solitary, free-living creature; every form of life is ______ other form.

单选题 It's well established that smoking cigarettes, especially large quantities of them, is bad for your health. But a new study shows the risk exists even with a minimal amount of smoking. Just one cigarette a day can increase the likelihood of cardiovascular (心血管的) disease. Researchers from University College London found that having a single cigarette each day raises the risk of coronary heart disease or stroke. 'No safe level of smoking exists for cardiovascular disease,' the authors conclude in their paper published Wednesday in BMJ. The team analyzed 141 previously published studies conducted between 1946 and 2015, which included data from millions of men and women. They specifically looked at the cardiovascular effects of people who smoked one, five or twenty cigarettes per day compared to those who had never smoked. When adjusting for confounding factors, such as age and blood pressure, they found that men who smoked one cigarette per day had a 74-percent higher risk of heart disease than non-smokers and a 30-percent higher risk of stroke. Among women, the risk of heart disease among one-per-day smokers was increased by 119 percent and the risk of stroke by 46 percent compared to non-smokers. 'There's a misconception by many smokers that if you cut down you will reduce harm,' Allan Hackshaw, a study co-author and epidemiology professor at University College London, told Newsweek. 'This seems to be true for lung cancer, but people aren't aware that only a little bit of tobacco smoke has a big effect on the cardiovascular system.' Although light smoking can negatively affect your health, cutting down is still helpful. 'I think a lot of people who work in the tobacco and the health industry right now forget how difficult it is to quit,' Hackshaw said. 'Going cold turkey is hard.' Hackshaw suggests finding an appropriate cessation (中止) method to help cut back. But he also emphasizes that the end goal should be to quit. One in every three deaths from cardiovascular disease is caused by smoking, according to the Centers for Disease Control and Prevention. Understanding the role of minimal smoking in this risk could help reduce the incidence of cardiovascular disease. Hackshaw and his colleagues hope their findings will be used to 'strengthen public health campaigns (including those on smoking cessation services) and to provide a strong health incentive for smokers to quit (particularly women), rather than cut down,' they wrote in their paper.

单选题The main aim of the WFP is to ______.

单选题But for your help, I ______ my work yesterday.

单选题One of the most {{U}}damaging{{/U}} plant parasites is the stem eelworm.

单选题Increasingly, over the past ten years, people—especially young people—have become aware of the need to change their eating habits, because much of the food they eat, particularly processed food, is not good for the health. Consequently, there has been a growing interest in natural foods. Foods which do not contain chemical additives(添加剂) and which have not' been affected by chemical fertilizers, widely used in farming today. (79) Natural foods, for example, are vegetables, fruit and grain which have been grown in soil that is rich in organic (有机的) matter. In simple terms, this means that the soil has been nourished by unused vegetable matter, which provides it with essential vitamins and minerals. This in itself is a natural process compared with the use of chemicals and fertilizers, the main purpose of which is to increase the amount—but not the quality—of foods grown in commercial farming areas. Natural foods also include animals which have been allowed to feed and move freely in healthy pastures(牧场). Compare this with what happens in the mass production of poultry: there are farms, for example, where thousands of chickens live crowded together in one building and are fed on food which is little better than rubbish. Chickens kept in this way are not only tasteless as food, they also lay eggs which lack important' vitamins. There are other aspects of healthy eating which are now receiving increasing attention from experts on diet. Take, for example, the question of sugar. This is actually a non-essential food ! Although a natural alternative, such as honey, can be used to sweeten food if it is necessary, we can in fact do without it. It is not that sugar is harmful in itself. But it does seem to be addictive: the quantity we use has grown steadily over the last two centuries and in Britain today each person consumes an average of 200 pounds a year! Yet all it does is to provide us with energy, in the form of calories. There are no vitamins in it, no minerals and no fiber. (80) It is significant that nowadays fiber is considered to be an important part of a healthy diet. In white bread, for example, the fiber has been removed. But it is present in unrefined flour and of course in vegetables. It is interesting to note that in countries where the national diet contains large quantifies of unrefined flour and vegetables, certain diseases are comparatively rare. Hence the emphasis is placed on the eating of whole meal bread and more vegetables by modem experts on "healthy eating".

单选题The Untied States and Canada are lands of ______ except for the Indians, who are the only true natives.