题目

如果方程x2+y2+Dx+Ey+F=0的曲线关于直线y=x对称,那么必有(    )A.D=E          B.D=F               C.E=F           D.D=E=F 答案：A解析:圆心(-,-)在直线y=x上,即D=E.Fill Her Tank FirstThe summer of 1975 I’d just graduated from college in Southern California and received a 1968 Ford Capri for a graduation present. I had my first job, in Los Angeles. One Sunday night, __36__ myself a very independent grown-up, I left my uncle’s place in South Laguna after a visit, without __37__ to him that I had less than an __38__ of a tank of gas and no cash to buy __39__ on the way to L.A. I pulled onto the Pacific Coast Highway and watched the needle __40__ as I headed north. When I started running on fumes, I pulled into a __41__. There was no self-service __42__; there were no credit cards, no ATMs.I begged the guy at the station. I __43__ write him a check for gas, I said, or I could sleep in my car and try to __44__ to a town with a bank the next morning. As he was informing me that I could sleep in my car but he’d have me __45__, a station wagon __46__ to the next pump. The driver--- a thin, plain, middle-aged guy---overheard the tail end of my __47__ request. As the attendant went to serve him, he nodded at me. “__48__ her tank first,” he said.“Really?” I said. Hope __49__. “Oh, thank you. Thank you. But please. I just need two dollars’ __50__. I just need to go home.”“Fill it,” he __51__ to the attendant. Then to me, “You will do the same one day, for someone else.”I keep looking for that unlucky young person, __52__ to save her night on the road. Meanwhile, in case she never __53__ up, I try for other acts of random kindness. That __54__ driver is always at the pump a few feet away, __55__ the attendant to fill mine first.小题1:A．thinkingB．hopingC．knowingD．showing小题2:A．confirmingB．convincingC．admittingD．concerning小题3:A．eightyB．eightC．eighthD．eighths小题4:A．anotherB．moreC．muchD．some小题5:A．dropB．increaseC．reduceD．decrease小题6:A．train stationB．bus stationC．railway stationD．gas station小题7:A．at one timeB．at a timeC．at timesD．at that time小题8:A．couldB．mightC．shouldD．must小题9:A．scrambleB．driveC．climbD．walk小题10:A．orderedB．helpedC．warnedD．arrested小题11:A．went upB．drove upC．pulled upD．drew into小题12:A．triedB．succeededC．reasonedD．failed小题13:A．FillB．FilledC．FillingD．To fill小题14:A．increasedB．raisedC．accumulatedD．fired小题15:A．valueB．worthyC．worthD．money小题16:A．pardonedB．repeatedC．saidD．spoke小题17:A．ensuringB．supposingC．hopingD．considering小题18:A．showsB．goesC．growsD．comes小题19:A．easy-goingB．politeC．powerfulD．quiet小题20:A．introducingB．instructingC．interestingD．interacting