题目

某种昆虫靠翅膀的振动而发声．如果这种昆虫的翅膀在2s时间内共振动了600次，则它翅膀振动的频率是_____Hz，我们_____听到该频率的声音（填“能”或“不能”）． 答案：【答案】 300 能【解析】（1）昆虫的翅膀在2s内振动了600次，（2）人类能听到的频率范围是20Hz～20000Hz，300Hz在人类能听到的频率范围内，所以能听到。故答案为：(1). 300 (2). 能 阅读下列材料，并从所给的六个选项(A、B、C、D、E和F)中选出符合各小题要求的最佳选项。选项中有一项是多余选项。 The people below are going to make a trip in Australia．After the description of these people, there is information about six advertisements of organized tours A-F．Decide which tour would be most suitable for the person mentioned in descriptions 61-65 and then mark the correct letter (A－F)．There is one extra paragraph about one tour which you do not need to use． ________1．Victor is fond of nature and adventure and he is making a study tour into geology in Australia．So he wants to make a whole day trip, enjoy the natural beauty and study geological phenomena as well． ________2．Vanessa is planning a short city tour of Sydney so that she can enjoy the highlights of the city and attend an important lecture given by Professor Brown Smith at 2：00p．m at the University of Sydney． ________3．Charlie and his friends are making their first journey in Australia．Having traveled around the city of Sydney, they plan to visit Canberra, the capital and political center of the country． ________4．Jenny, a European woman with her children is visiting her relatives in Australia．They want to relax themselves by enjoying the sunshine on the sandy beaches along the coast and have fun with dolphins． ________5．Mike and Susan are from Brazil．They have been traveling in Australia for a couple of days．This weekend, they would like to have a change and travel to the countryside to have some idea of Australia grape farming and wine producing instead of making city tours around． A．City Highlights, Manly Beach, Northern Beaches Tour the highlights of Sydney, then cross the Sydney Harbor Bridge to Manly and the Northern Beaches．Capture the beauty and lifestyles of the harbor city form Gray Line’s specially selected vantage points． Departs：8∶30 a.m．Adult：$51.00 Returns：11∶50 a.m．Child：$25.50 B．New Parliament House, National Museum, Australian War Memorial The nation’s capital－a purposely built city, ultra modern, with imposing architecture yet a rural charm of lakeside, gardens and open spaces．This hi-tech city is the seat of Parliament and home of superb national monuments, museums and galleries． Departs：8∶30 a.m． Adult： $110.00 Returns：9∶15 p.m． Child： $55.00 C．Cuddle a Koala, Kangaroos, Harbour Luncheon Cruise Observe and meet our unique native animals with ample opportunity to get to know the Cuddly Koala．Then enjoy a spectacular luncheon cruise on beautiful Sydney Harbour．You can choose between the Matilda Cruises Sailing Catamarans, the stream-lined Captain Cook Cruisers or Magistic Cruises． Departs： 8∶40 a.m．　Adult： $115.00 Returns： 2∶00 p.m．　Child： $57.50 D．Hunter Valley Wineries, Wine Tasting, Traditional Aussie Towns World acclaimed Australian wines from the vineyards of the rolling hills and valleys’ of the Hunter region．The Hunter Valley is Australian’s oldest commercial wine producing district with over 7,000 acres under vine．Visit historic Wollombi and the Old Travern, tour Cessnock and the lower Hunter Valley noted for its early Australian townships and try local cheeses that compliment fine wines． Departs：8∶40 a.m Adult：$127.00 Returns：6∶40 p.m Child：$63.50 E．Post Stephens, Central Coast Beaches, North Coast, Dolphin Watching Discovering the beautiful Central Coast north of Sydney with its holiday villages, white sandy beaches and the sparkling Pacific Ocean．Ride the wave crests with the Dolphins in the azure waters of sheltered pot Stephens where forests, villages and stately homes meet with the sea．This quiet arm of the blue Pacific Ocean is home to a pod of nature’s most lovable and intelligent marine mammals． Departs：8∶30 a.m．Adult：$126.00 Returns：7∶00 p.m．Child：$ 63.00 F．Jenolan Caves, Blue Mountains, Adventure Caves The Blue Mountains National Park is a kaleidoscope of contrasts and colour rich in Australian bush and wildlife, always with a distant blue haze horizon．Spectacular Jenolan Caves－the brilliance and timelessness of nature are revealed．Be enthralled with the beauty of these ancient limestone caves． Departs：8∶40 a.m．Adult：$114.00 Returns：6∶40 p.m．Child：$57.00