题目

物体在周期性驱动力作用下做受迫振动，固有频率为f1，驱动力的频率为f2，物体做受迫振动的频率为f，则（   ）A．f = f1         B．f = f2       C．f＞f1                D．f＜f2  答案：B解析:物体做受迫振动的频率等于驱动力的频率，则受迫振动的频率为f= f2，B正确。 Makoto、Mr. Zheng、Mr. Zhu、Jack 和Xiao Wang 正在广州寻找合适的餐厅，下列各题是对他们个人情况的介绍。阅读下列餐厅的信息(A、B、C、D、E、F)，选出符合他们各人需要的最佳选择。选项中有一项是多余的。【小题1】 Makoto is a Japanese tourist who has stayed in Guangzhou for a few days. He wants to make a tour of North China but unfortunately he has no time. So he would like to find a restaurant where he can taste northern food and experience the life in the north.78. 【小题2】 Mr. Zheng was born in Hunan but went to Japan at an early age. This time he came to Guangzhou to deal with some business affairs. Coming back to his homeland after being away for about 20 years, he hopes to find a restaurant serving food of his home town.79. 【小题3】 It is the first time for Mr. Zhu, who comes from the northeast of China, to visit Guangdong Province. He is interested in traditional Cantonese food and Cantonese lifestyle.80. 【小题4】Jack is a successful businessman. He is flying to Guangzhou to meet some people, who are likely to sign a contract with him. He wants to find a high quality restaurant. Of course, it is the quality rather than the price that he cares about.81. 【小题5】Xiao Wang, a migrant worker in Guangzhou, plans to hold a party with his 10 friends. All of them are fond of the Sichuan cuisine. Xiao Wang hopes to spend less than 600 yuan for the dinner.ANanhai Yucun RestaurantFounded in 1986, Nanhai Yucun Restaurant has always been one of the gourmets’ choices in Guangzhou.Prices are high, but so is the quality. Just look at the gust list; the King and Queen of Spain, South Korea’s Prime Minister and his wife have eaten here, along with lots of local famous people. BDongbeirenDongbeiren is meant for northerners. The decoration is basically red—from the paper cuts and the curtains to the Kang (a bed with a table where people can sit comfortably without shoes and with their legs folded). It is perhaps a way to remind the northerners of home or for other people to get in touch with the north.  CTaotaoju RestaurantTaotaoju Restaurant is one of Guangzhou’s most well-known traditional Cantonese restaurants, located in a historic building in the heart of the city’s Xiguan District.You can’t get any more traditional Guangzhou than this, which is a great place for dim sun and seafood. You haven’t lived in Guangzhou until you’ve eaten dim sum in a true local place like Taotaoju. It’s also a popular spot for parties. DChongqing Xiaodongtian RestaurantIt’s one of the top Sichuan cuisine restaurants in Guangzhou, featuring Chongqing flavor.It is a group of chain restaurants in Guangzhou. The food is Sichuan style, but the decoration and surroundings are a bit old.Like most Sichuan restaurants, the pleasant smell of their traditional hot pot spreads throughout the whole place.Food here is medium-priced, around 50 RMB per person. EMaojia ReastaurantMaojia Reastaurant is a local favorite for strong-flavored Hunan dishes.It has a strong cultural atmosphere related to Chairman Mao and also introduces Maojia dishes characteristic of tasty Hunan local flavors, which are a bit softer than the traditional Hunan flavor. FEnmi Japanese ReastaurantThe decoration here is beautiful and peaceful.A small “courtyard of bamboo” is refreshing while the space between tables is large and comfortable. The diverse sashimi (raw fish slices) is a must-try here.The food, however, is served slow and the regulated tow hours for ordering is strange.