题干

设a∈R,则“a=2”是“直线l1:x+ay﹣a=0与直线l2:ax﹣(2a﹣3)y+1=0垂直”的(   )

A:充分但不必要条件

B:必要但不充分条件

C:充要条件

D:既不充分也不必要的条件

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答案(点此获取答案解析)

A

同类题1

阅读下面短文,掌握其大意,然后从36—55各题所给的四个选项(A、B、C和D)中,选出最佳选项,并在答题卡上将该项涂黑。

    Every day, I drive home along Colorado Blvd, a wide street with four lanes on each side of the median (中央分隔带护栏). I always notice a homeless man standing on the corner of Colorado Blvd, 1 for spare change with a sign in his hand.
Last Monday, when I was 2 him, he suddenly threw down his sign and rushed into the middle of the street. At this time I 3 a car moving across the 3 lanes of traffic and heading for the  median. The 4 man ran to the side of the car and attempted to push the car back in the right 5. He also knocked on the window of the vehicle, but all  6 Immediately, he ran across the small median into four lanes of oncoming traffic, 7 madly for the cars to stop. Thankfully, all speeding cars 8 to stop just in time to 9 hitting him. The car which was out of 10 came Moving across the median and the four lanes of traffic, where just seconds ago cars had been traveling with 11 speeds.
    The homeless man jumped back in front of the 12 to attempt slowing it down again. By this time, we were able to 13 and help the man stop the car 14 it ran into a supermarket on the other side of the road. As it 15 out, the woman driver had a heart attack while driving and became 16 in the front seat.
    The homeless man is indeed a hero. He spends every day getting 17 by people who are trying not to make 18 contact with him so that they don't feel bad not giving him money. Yet he didn't  even hesitate to risk his life to save this lady and other drivers who would have 19 into her. He didn't think of his safety, nor did he expect anything in return. Heroes do exist in the most 20 places.

同类题4

五千年的中华文化,熠熠生辉,璀璨夺目,如何正确认识和发展中华传统文化是与下社会发展的一个重要命题。

材料一:“多彩中华”是一个由中国民族博物馆创建,文化部、外交部支持的少数民族文化对外交流品牌项目。该项目主要展示各民族文化:无伴奏多声部合唱的侗族大歌,古老而优美的羌族舞蹈,热情而艳丽的新疆舞蹈,传统的中国民族乐器琵琶、二胡和古筝等。各民族文化不仅各具特色还相互交流和借鉴,传递出了中华文化“和善”、“祥和”、“和而不同”的价值追求和精神面貌,展示出了各民族亲如一家的和谐关系。

材料二:中华文化五千年的历史创造出了丰富而绚丽的古诗词,但如今一些人对古典诗词不再关注,侃侃而谈,一提起古诗词人们莫不把它与老古董相联系,认为繁琐的要求,隐晦的修饰,文绉绉的表达都与今天的时代不相符合,因此没必要重视发展古诗词,应淡化古典诗词。但也有人认为对待古诗词的态度传递的是对待经典传统文化的态度,对古诗词的淡化是对传统文化的否定,中国古典诗词所包含的讲仁爱,守诚信,崇正义,求大同等思想仍具有时代价值。因此我们不仅不能淡化古典诗词,还必须强化对古典诗词的研究和发展。

材料三:在争创全国文明城市进程中,具有悠久历史的某市交出了一份令人满意的答卷。该市依托深厚的文化底蕴,通过历史古迹保护和开发、街区复原和翻新、传统技艺发现之旅等方式深度挖掘历史文化的现实意义;同时又借鉴了其他发达城市的文明建设经验,使得一座座现代建筑拔地而起,让这个历史厚重的故都焕发出蓬勃的朝气和昂扬的锐气;其次该市充分利用网络、微信、微博等新兴传播平台,营造强大的舆论氛围,使创建工作家喻户晓,人人皆知;最后备街道、社区积极开展“文明村镇”、“文化社医”等活动,通过改善环境,改善民生,提高市民参与创建工作的主动性和积极性。这些措施都极大的丰富和提升了该市的文化内涵,实现了文明城市创建工作的成功。