题目

设全集，集合，则（    ）    A．      B．      C．      D． 答案：A  解：全集,集合  根据补集定义可得 则  故选:A1．In the winter months the temperature in most of Canada usually stays below 0℃．However，in some parts of Canada，such as southern British Columbia，the temperature rarely goes below 0℃．In most areas where people live，snow will be on the ground from mid-December to mid-March．Though Canada's winter may be much colder and longer than you are used to，it can be very enjoyable．For many Canadians，being active in winter is an important part of enjoying life．There are many outdoor winter activities，including skiing，ice fishing，walking，and skating．Joining in one of these activities may help you appreciate winter and enjoy your time outside in the snow．Drssing for winterDuring winter in Canada，you will need warm clothing．If possible，arrive with these items or be prepared to buy them soon after your arrival．You will need：☆warm waterproof boots☆a scarf for your neck☆a hat that covers your ears☆gloves for your hands☆thick winter coats，pants and sweatersLayers keep you warmIt's a good idea to layer your clothing by，for example，wearing a T-shirt and a sweater underneath a jacket．If you become too hot，it's always easier to remove a piece of clothing than to add another．On the West Coast，prepare to dress for cool rainy or snowy weather．You will need：☆a warm waterproof coat☆waterproof hats☆an umbrella☆rain boots or snow bootsLearn more about weather and seasons across Canada．You can also contact Related Links，for example，an immigrant serving organization in the community where you live for more information about dressing for winter．25．What is the main purpose of the first paragraph？DA To tell about the details about Canada．B．To show many outdoor winter activities．C．To introduce the daily life of Canadians．D．To encourage you to enjoy winter in Canada．26．What is the important part for many Canadians in winter？CA．Ice fishingB．Joining a group．C．Leading an active lifeD．Staying in the snow．27．If you spend a winter in Canada，you'll prepare the following EXCEPTA．A．an umbrella and sunglasses          B．thick winter coats and pants C．waterproof hats and coats            D．snow boots and gloves28．The author suggest layering your clothing probably becauseC．A．it is cool to dress like that           B．it is a rule to dress like that C．the weather there is changeable       D．the weather is usually very hot．