题干

下列叙述正确的是(   )

A:在东南亚发展水稻种植业可以缓解人口对土地的压力和对粮食的需求

B:商品谷物农业主要种植的粮食作物是水稻和小麦

C:新西兰是世界羊毛出口最多的国家

D:潘帕斯草原的牧牛业与澳大利亚墨累-达令盆地的牧羊业属于同一种农业地域类型

上一题 下一题 0.0难度 选择题 更新时间:2018-11-06 09:43:18

答案(点此获取答案解析)

A

同类题2

完形填空:阅读下面短文,从短文后各题所给的四个选项(A、B、C和D)中,选出可以填入空白处的最佳选项。

    Mrs. Hammond was old and blind, but she was determined to do everything for herself. She even used to go for walks by herself once a day for 1, and found her way by 2 things with her white stick. She learned where everything was, so she never lost her way.

    One day, some men came and cut down some of the familiar trees at the side of one of the paths which she 3. When she reached that place that evening, she did not 4 the trees with her stick, so she was in 5.

    She 6 for a while and listened, but did not 7 any other people, so she went for a kilometer or two, and then she heard  8 beneath her. “Am I 9? I suppose so,” she said, “I must be on a 10, and there must be a river under me. I've been told that there's a river in this part of the country, but I don't know its exact 11. How am I going to get 12 to my house from her e?”

   All at once she heard a man's friendly 13 near her. “Excuse me, can I help you?”“How kind of you!” Mrs. Hammond answered. "Yes, please. Some of the trees which I follow have been  14 today, and if I hadn't been 15 enough to meet you, I don't know 16 I'd have done. Can you please 17 me to get home?”

 “ Certainly,” the man answered. “Where do you live?”

    Mrs. Hammond told him, and the man took her to her house . She told the man how pleased she was that she had met him. But the man said. “I want to 18 you.”

    Mrs. Hammond asked, “Whatever for?”

   “Well,” the man said quietly, “I was balanced (悬在) on the edge of that bridge for ages in the 19, because I was trying to make up my mind to 20 myself into the river and drown myself. But I'm not going to do it now.”

同类题4

阅读下文回答问题。

你了解空气清新剂吗

      近日,河南长垣县一家歌舞厅发生火灾,造成11人死亡24人受伤,起火原因竟是电热器烘烤空气清新剂,使其1分钟内连爆近10次。此事引发人们对常用空气清新剂的重新认识。

      很少有人想到,空气清新剂会是一种易燃易爆物品。液体空气清新剂其实是一种气雾剂,其中的抛射剂,包括不燃性和可燃性两类。前者为氟烃类物质(如氟利昂),后者为低级饱和性碳氢化合物(丙烷、丁烷等)和醚类(二甲醚)。此外,也有使用压缩性气体增加气雾剂罐中的压力的产品。由于许多气雾剂和喷雾剂原液中含有可燃性物质,无论在生产、运输和使用过程中,都可能发生爆炸。

      在现实生活中,不少家庭为了防止居室产生污浊空气,往往用“香”来除臭。单从名字上看,空气清新剂应该能使空气清洁、气味清新。其实不然,空气清新剂名不符实,它是靠香味遮掩异味,并不能真正改善空气的质量。释放到空气中,本身就是一种污染物质,会在去除某种污染物或多或少的同时引入新的污染物(如氟利昂等)。早在2012年9月,中科院专家就通过对市面上常见的空气清新剂进行检测发现,绝大部分空气清新剂,超过40%的成分是萜类化合物,而这些化合物会与空气中的臭氧反应,生成甲醛和粒径小于0.1微米的超细微粒

      研究发现,带有某种馨香气体的挥发性溶剂被人体吸入后,会很快被吸收并侵入神经系统,使人产生“镇静”感。专家分析,这种药效与中枢神经镇静剂相近,当嗅者体验到某种感受后,会产生精神依赖。成瘾者选择自己喜欢的溶剂,强制性的每日重复吸入,结果引起慢性中毒。

      因此,专家建议,除非特殊需要,应尽量减少空气清新剂的使用。尤其在日照强烈,易于生成臭氧的夏秋季节。当然,专家也特别强调,并不是市面上所有的空气清新剂都有毒害作用。如果选择较为知名的空气清新剂品牌,其成分是从天然植物中提取的,不含氯氟烃,或许会可靠一些。

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