题目

如图3所示，起重机将货物沿竖直方向匀加速吊起，同时又沿横梁水平匀速向右运动。此时，站在地面上观察，货物运动的轨迹可能是图4中的( ) 图3 图4 答案：C 货物向右匀速运动，向上匀加速运动，其运动轨迹为曲线，并且是抛物线，曲线应向加速度方向弯曲，故C正确。Puerto Rico may be part of the USA but its music and dance is a mixture of both Spanish and African rhythms. The country, as a result, is a mixture of very new and very old. It exhibits the open American way of yet retains the more formal Spanish influences. This is reflected in the architecture, not just the contrast between the colonial and the modern in urban areas but also in the countryside, where older buildings sit side by side with concrete schools and buildings. However, if you do not wander beyond the tourist areas on the coast, you will not experience the real Puerto Rico. Old volcanic mountains, long inactive, occupy a large part of the interior（内陆）, with the highest peak, Cerro de Punta, at 1,338m in the Cordillera Central. North of the Cordillera is the karst （岩溶）country where the limestone（石灰石）has been acted upon by water to produce a series of small steep hills and deep holes. The mountains are surrounded by a coastal plain with the Atlantic shore beaches cooled all the year round by trade winds. The population is 3.8 million, of which about 1.5 million live in San Juan, although about another two million Puerto Ricans live in the USA Average life expectancy is 73.8 years and GDP per capita is US $12,212, the highest in Latin America, although not up to the level of mainland USA. Most Puerto Ricans do not speak English and less than 30% speak it fluently. Second generation Puerto Ricans who were born in New York but who have returned to the island, are called Nuyoricans. The people are very friendly and hospitable but there is crime, liked to drugs and unemployment.小题1:What are the disadvantages of Puerto Rico?A．Too many Puerto Ricans live in the USAB．Few people in Puerto Rico can speak EnglishC．Puerto Rico’s GDP is lower than that of the USAD．Social problem connected with drugs and lack of jobs.小题2:We can learn from the passage that Puerto Rico _________.A．is a state of the United StatesB．used to be ruled by SpainC．is an agricultural countryD．is gently affected by Africa小题3:Nuyorican is a person who _______.A．has been living in New YorkB．is living in New YorkC．was born in New York but has returned to Puerto RicoD．has got the citizenship of America小题4:What does the underlined word “retains” mean?A．losesB．keepsC．enjoysD．returns