题目

两个质量相等的小铁快A和B，分别从两个高度相同的光滑斜面和光滑圆弧斜坡的顶端由静止开始滑向底部，如图所示，则下面说法不正确的是（                                           ）                                                                                                            A．  下滑过程中重力所做的功相同    B．  它们到达底部时动能相同    C．  17．It is well-known that twins are closer to each other than most brothers and sisters----after all，they probably spend more time with each other．Parents of twins often notice that they develop special ways of communicating：they invent their own words and one can often finish the other's sentence．In exceptional circumstances，this closeness becomes more extreme：they invent a whole language of their own，as in the case of Grace and Virginia Kennedy from Georgia in the USA，who communicated so successfully in their own special language that they did not speak any English at all until after they started school．However，these special relationships are the result of lives spent almost entirely in each other's company．What happens when twins do not grow up together，when they are separated at birth for some reason？Are they just like any other strangers，or are there still special similarities between them？Professor Tom Bouchard，of the University of Minnesota，set out to find the answer to this question．He traced sixteen pairs of twins，who were adopted by different families when they were babies，and often brought up in very different circumstances．Each twin was then interviewed about every small detail of their life．The results of this research make a surprising reading．Many of the twins were found to have the same hobbies，many have suffered the same illnesses，and some have even had the same type of accident at the same point in their lives．One pair of middle-aged women arrived for their first meeting in similar dresses，another pair were wearing similar jewellery．The most incredible similarities are to be found in the case of Jim Springer and Jim Lewis from Ohio in the USA．The story of the'Jim Twins'made headline news across USA．Born to an immigrant woman in 1939，and adopted by different families at birth，both babies were named Jim by their new parents．But what can be the explanation for these remarkable similarities？Is it all pure coincidence，or is the explanation in some way genetic？Research into the lives of twins is forcing some experts to admit that our personalities may be at least partly due to'nature'．On the other hand，analysts are also anxious to emphasise that incredible coincidences do happen all the time，not just in the lives of twins．73．The case of Grace and Virginia Kennedy （Para.1）is to show thatA．A．twins communicate with each other in an unusual way B．twins are more likely to suffer from speaking problemsC．most twins have exceptional abilities to invent a new languageD．twins won't have an effective communication until they go to school74．The purpose of Tom Bouchard's study is to findC．A．what will happen if twins spend lives entirely in the same company B．why the 16 pairs of twins have been adopted by different familiesC．whether separated growing up has effect on twins'special similaritiesD．when the special similarities come into being during their growing up75．What does the word"reading"in Paragraph 3 most probably mean？BA．Book．B．Interpretation．C．Literature．D．Measurement．76．According to Tom Bouchard's research，the special similarities between twinsDA．depend on what the twins enjoy and suffer from B．can not be proved or accepted by all the experts C．result from the twins'growing up and developmentD．are not closely linked with where the twins are raised 77．What can be learned from the last paragraph？CA．Incredible coincidences happen to twins all the time．B．Nature is the only way to explain the similarities between twins．C．The differences between twins are to some extent the results of genes．D．Similarities shows the close relationship between two strange persons．