(The age of) a geological sample can (be estimated) from the ratio of radioactive to nonradioaetive carbon (present) in the object (is examined).
A.The age of
B.be estimated
C.present
D.is examined

未分类题It is hard to predict how science is going to turn out, and if it is really good science it is impossible to predict. If the things to be found are actually new, they are by definition unknown in advancE.You cannot make choices in this matter. You either have science or you don't, and if you have it you are obliged to accept the surprising and disturbing pieces of information, along with the neat and promptly useful bits.The only solid piece of scientific truth about which I feel totally confident is that we are profoundly ignorant about naturE.Indeed, I regard this as the major discovery of the past hundred years of biology. It is, in its Way, an illuminating piece of news. It would have amazed the brightest minds of the 18th century Enlightenment to be told by any of us how little we know and how bewildering seems the way aheaD.It is this sudden confrontation with the depth and scope of ignorance that represents the most significant contribution of the 20th century science to the human intellect. In earlier times, we either pretended to understand how things worked or ignored the problem, or simply made up stories to fill the gaps. Now that we have begun exploring in earnest, we are getting glimpses of how huge the questions are, and how far from being answereD.Because of this, we are depresseD.It is not so bad being ignorant if you are totally ignorant; the hard thing is knowing in some detail the reality of ignorance, the worst spots and here and there the not-so-bad spots, but no true light at the end of the tunnel nor even any tunnels that can yet be trusteD.But we are making a beginning, and there ought to be some satisfaction. There are probably no questions we can think up that can't beanswered, sooner or later, including even the matter of consciousness. To be sure, there may well be questions we can't think up, ever and therefore limits to the reach of human intellect, but that is another matter. Within our limits, we should be able to work our way through to all our answers, if we keep at it long enough, and pay attention.According to the author, really good science ______.A.would surprise the brightest minds of the 18th century EnlightenmentB.will produce results which cannot be foreseenC.will help people to make the right choice in advanceD.will bring about disturbing results

未分类题听力原文：W: Exercise, exercise, exercisE.We hear so much about it these days, yet even the experts can't agree on which exercises are best. Now some doctors are strongly encouraging arm exercises.M: Arm exercises? Is that because our arms are too fat or flabby?W: Actually, that's not the main reason. They say that arm exercises are an ideal way to become physically fit.M: But don't arm exercises raise your blood pressure?W: That they do. But the article I read mentioned ways to compensate for that.M: How?W: By adding leg exercises, so the arms don't do all the work. Ann exercises alone aren't enough to increase metabolism before fatigue sets in. The more of the body that's involved in the exercise, the better.M: And in turn, I'm sure that there's a greater chance of losing weight.W: Sounds right to mE.M: So what exercises do the experts recommend?W: They mentioned quite a few but some of the more popular ones are cycling with special bicycles that make you use both your arms and legs, and walking vigorously while you wear arm weights.M: I must try that, I like to walk a lot.(23)A.They don't get rid of flabby arms.B.They can damage arm muscles.C.They aren't acceptable to most peoplE.D.They can raise one's blood pressurE.

单项选择题‍目前，在大型乒乓球赛事中，多采用 和 两个成熟的软件。​ ​

未分类题听力原文： There are two kinds of memory: short-term and long-term. Information in long-term memory can be recalled at a later time when it is needeD.The information may be kept for days and weeks. In contrast, information in short-term memory is kept for only a few seconds, usually by repeating the information over and over. The following experiment shows how short-term memory has been studieD.Henning studied how students who are learning English as second language remember vocabulary. The subjects in his experiment were 75 college students. They represented all levels of ability in English: beginning, intermediate, advanced, and native-speaking students. To begin with, the subjects listened to a recording of a native speaker reading a paragraph in English. Following the recording, the subjects took a 15-question test to see which words they remembereD.Each question had four choices. The subjects had to circle the word they had heard in the recording. Some of the questions had four choices that sounded alikE.For example, weather, whether, wither, and wether are four words sound alikE.Some of the questions had four choices that have the same meaning. Method, way, manner, and system would be four words with the same meaning. Finally the subjects took a language proficiency test.Henning found that students with a lower proficiency in English made more of their mistakes on words that sound alike; students with a higher proficiency made more of their mistakes on words that have the same meaning. Henning's results suggest that beginning students hold the sound of words in their short-term memory, and the advanced students hold the meaning of words in their short-term memory.(33)A.To study how students remember English vocabulary by short-term memory.B.To study how students learn English vocabulary.C.To study how to develop student's ability in English.D.To study how long information in short-term memory is kept.

未分类题危险化学品安全技术本部分共10小题，每小题1分。每题的备选项中只有一个最符合题意。危险化学品的主要危险特性是( )。D.火灾、失效、中毒、腐蚀及污染环境

单项选择题_____污泥适合采用气浮浓缩法。

未分类题张某委托刘某购书，并将一本存有3万元人民币的全国通兑活期存折交给刘某用于买书。刘某在途中取出该存折的3000元用于购买毒品，被公安机关当场抓获。审讯中，刘某供述存折中余下的1万元仍打算用于购买毒品。县法院对刘某判处有期徒刑15年。随后，公安机关作出行政处罚决定，关于当场查获的3000元和存折内的余款，正确的处理方法是( )。D.没收用于购买毒品的3000元，将存折内余款返还张某

单项选择题平飞时飞机重心会在纵向前后移动，需要不断调整操纵面保持平衡，此过程称为( )。 A、俯仰配平 B、俯仰操纵 C、方向操纵 D、方向配平

单项选择题- Quelle est votre nationalité ? - Je（ ）allmande. A、 es B、 suis C、 est D、 être

未分类题Most children with healthy appetites are ready to eat almost anything that is offered them and a child rarely dislikes food (1)_____ it is badly cookeD.The (2)_____ a meal is cooked and served is most important and an (3)_____ served meal will, often improve a child's appetitE.Never ask a child (4)_____ he likes or dislike a food and never (5)_____ likes and dislikes in front of him or allow (6)_____ else to do so. If the father says he hates fat meat or the mother (7)_____ vegetables in the child's hearing he is (8)_____ to copy this procedurE.Take it (9)_____ granted that he likes everything and he probably (10)_____. Nothing healthful should be omitted from the meal because of a (11)_____ dislikE.At meal times it is a good (12)_____ to give a child a small portion and let him (13)_____ back for a second helping rather than give him as (14)_____ as he is likely to eat all at oncE.Do not talk too much to the child (15)_____ meal times, but let him get on with his food: and do not (16)_____ him to leave the table immediately after a meal or he will (17)_____ learn to swallow his food (18)_____ he can hurry back to his toys. Under (19)_____ circumstances must a child be coaxed (20)_____ forced to eat.A.ifB.untilC.thatD.unless