题目

甲、乙两车在平直的公路上向相同的方向行驶，两车的速度v随时间t的变化关系如图所示，其中阴影部分面积分别为S1、S2 ， 下列说法正确的是() A . 若S1=S2 ， 则甲、乙两车一定在t2时刻相遇 B . 若S1>S2 ， 则甲、乙两车在0-t2时间内不会相遇 C . 在t1时刻，甲、乙两车加速度相等 D . t1-t2时间内，甲车的平均速度v<The British National Health Service（NHS） was set up in 1948 and was designed to provide equal basic health care, free of charge, for everybody in the country．Before this time health care had to be paid for by individuals. Nowadays the central government is directly responsible for the NHS although it is administered by local health authorities．About 83 percent of the cost of the health service is paid for by general taxation and the rest is met from the National Insurance contributions paid by those in work．There are charges for prescription and dental care but many people, such as children, pregnant women, pensioners, and those on Income Support, are exempt from payment. Most people are registered with a local doctor （a GP, or general practitioner） who is increasingly likely to be part of a health centre which serves the community. As the population of Britain gets older, the hospital service now treats more patients than before, although patients spend less time in hospital．NHS hospital — many of which were built in the nineteenth century — provide nearly half a million beds and have over 480,000 medical staff．The NHS is the biggest employer in Europe although Britain actually spends less per person on health care than most of her European neighbors. During the 1980s, there was considerable restructuring of the Health Service with an increased emphasis on managerial efficiency and the privatization of some services （for example, cleaning）．At the end of the 1980s, the government introduced proposals for further reform of the NHS, including allowing some hospitals to be self-governing, and encouraging GPs to compete for patients．Patients would be able to choose and change their family doctor more easily and GPs would have more financial responsibility．The political questions continue of how much money should be provided to support the NHS and where it should come from. 1．We know from the first paragraph that ______.        A．patients were charged for receiving health care before 1948        B．people didn’t have to pay for health care before the NHS was set up        C．the NHS was an organization which gave free advice to villagers        D．the original aim of the NHS was to provide equal basic health care for everybody 2．What do we know about the NHS?        A．It’s managed by the central government.        B．It hires more people than any other unit in Europe.        C．Its cost is mainly paid for by the National Insurance contributions.        D．Fewer patients go to its hospitals than before because they spend less on health care. 3．All the following statements about GPs are true EXCEPT that they ______.        A．take care of the local people’s health        B．have more responsibilities than before        C．work under high pressure nowadays        D．often take part in competitions to see who is the best 4．The underlined word “exempt” probably means ______.        A．suffering         B．different          C．prevented           D．free