题干

下列关于糖类物质对应正确的是(  )

①存在于DNA而不存在于RNA中的糖类

②细胞的重要能源物质

③存在于动物细胞中的多糖.

A:核糖、纤维素、糖原

B:脱氧核糖、葡萄糖、糖原

C:核糖、葡萄糖、糖原

D:脱氧核糖、脂肪、乳糖

上一题 下一题 0.0难度 选择题 更新时间:2017-10-14 10:16:39

答案(点此获取答案解析)

B

同类题4

完形填空

    On August 26,1999,New York City experienced a torrential downpour.The rain caused the streets to1and the subway system almost came to a stop.

    Unfortunately, this happened during the morning rush hour.Many people who were going to work were2to go home.Some battled to3a taxi or to get on a bus.Still others faced the4bravely,walking miles to get to work.

    I 5 to be one of the people on the way to work that morning.I went from subway line to subway line only to find that most6had stopped.After making my way7crowds of people,I finally found a subway line that was 8.Unfortunately,there were so many people waiting to9the subway that I could not even get down the stairs to the10.So I took the train going in the opposite direction,and then switch back to the downtown train.Finally,after what seemed like an forever,the train11my stop.Then I had to walk several blocks in the increasingly heavy rain. When I finally got to my office,I was12through,exhausted and13.

    My co-workers and I spent most of the day drying off.When it was 5:00 pm,I was ready to go home.I was about to turn off my computer14I received an email from Garth,my Director:

    I would like to thank all of you who made the effort and15reported to work.It is always reassuring(今人欣慰),at times like these,when employees so clearly show their16to their jobs.Thank you.

    Garth's email was short, but I learned more from that17message than I ever did from a textbook.The email taught me that a few words of18can make a big difference.The rainstorm and the traffic19had made me tired and upset.But Garth's words immediately20me and put a smile back on my face.

同类题5

阅读下面的文字,完成下列小题。

材料一:

    随着我国城镇化进程的加快以及人民生活水平的提高,生活垃圾的总量也在不断加大,部分城市在市郊露天堆放垃圾,对天气、土壤、水的环境造成污染。大量餐厨垃圾与其他垃圾混合填埋或焚烧,产生有毒物质,威胁着居民健康,这种现象正在向农村地区漫延。

    垃圾分类作为垃圾处理的前端环节,其作用早已得到世界的公认,分类收集不仅能大幅度减少垃圾给环境带来的污染,节约垃圾无害化处理费用,更能使资源得到重复利用,有人将垃圾称为“放错了地方的资源”,据保守估计,我国城市每年丢弃的可回收垃圾价值在300亿元左右。但我国的垃圾分类工作一直难以有效推进,相关调查显示,约四分之一的受访者认为垃圾分类效果不明显或完全没有效果。

材料二:

    笔者所在的小区,居民楼前三个垃圾桶分别表示出应放置可回收物、其他垃圾和餐厨垃圾。可是大多数居民还是把垃圾混杂在一起,一扔了之。问及原因时,有人说:“我辛辛苦苦分了类,环卫车辆却混在一起运走了,分类还有什么意义?”

    这种现象可以说是屡见不鲜,垃圾分类处理是个复杂的系统工程,包括分类投放、分类收集、分类运输、分类处理,各个环节必须配套衔接,才能高效运行。分类投放是居民的责任,分类收集、分类运输、分类处理是政府的责任。分类投放的参与率和准确率较低,会影响垃圾分类制度的实施效果;而分类的目标和途径不十分清晰,后端分类处理不到位、不完善,又影响前端居民分类的积极性。

    前不久,国务院办公厅转发国家发改委、住建部《生活垃圾分类制度实施方案》,给出了我国推进垃圾分类的总体路线图。但是,这一方案即使再科学合理,如果缺乏全民动员、全民参与,也难以由蓝图变为现实。我们应当认识到,生活垃圾虽然有资源属性,但污染属性更不可忽视。不按要求扔垃圾,并不只是“把资源放错了地方”而已,实际上,那就是随意丢弃污染物、危害环境的行为。垃圾分类是我们作为“污染者”的基本责任,责无旁贷。当然,各地政府同样不能以“居民没有分类”“缺乏资金”等理由拖延、观望,应当落实政府主体责任,坚持政府主导,根据本地特点,做好分类收集、分类运输、分类处理设施体系建设,同时制定完善的惩罚和奖励的政策措施。

    随着生态文明建设的持续推进、国民素质的提升和垃圾处理设施的进步,普遍推行垃圾分类制度的条件已经成熟。重要的是,居民和政府快把自家的“门前雪”打扫干净吧!各负其责,各尽气力,形成合力,减量化、资源化、无害化的目标一定能够实现,垃圾分类前景可期。

(摘编自刘毅《垃圾分类应自扫门前雪》,2017年5月6日《人民日报》)