题干


(陕西卷16)._____from the top of the tower, the south foot of the mountain is a sea of trees.   

A:See

B:Seeing

C:Have see

D:To see

上一题 下一题 0.0难度 选择题 更新时间:2019-06-15 09:05:21

答案(点此获取答案解析)

A

同类题3

阅读下面文章,完成下列小题。

冬眠的奥秘

张劲硕

    ①严寒的冬天,我们总是向往着在被窝里长眠一冬——能像狗熊和青蛙那样冬眠就好了。然而我们大都不知道:那些冬眠的动物们,掌握着我们人类尚不知晓的惊天奥秘。

    ②冬眠是动物应对恶劣环境的一种策略,科学上叫“蛰伏”。有人会问,冬天里睡得多、睡得久,不就是冬眠吗?它们还真不是一回事儿,只是二者的区别不太容易看出来。拿鱼来说,有几类鱼是会冬眠的,包括我们熟悉的鲤鱼、乌鳢,还有海里的鳗鲡。每当冬天来临,它们就把自己调到冬眠档:不吃、不喝、不游动。这看似与正常档的睡觉并无二致,但请注意它们的鳃!鱼类靠鳃呼吸,平时就算身体静止不动,鳃也会轻轻开合扇动。而进入冬眠的鱼,鳃也几乎不动,完全处于麻痹状态。除了呼吸,冬眠动物的体温、心跳等生命体征也都降到极低的水平,新陈代谢速率变得非常缓慢,与休克和死亡标准只差那么一点点——这就是冬眠与睡觉的本质区别。

    ③冬眠的意义在于,尽量减少身体内外的生命活动,将能量消耗降到最低,以挨过环境严酷的时间段。动物冬眠时,能把生命的时钟调得极慢。比如生活在北美洲的普通箱龟,冬眠时心脏5-10分钟才跳1次,实在让人惊叹。更夸张的是,它们几乎不呼吸,只靠皮肤吸入少许氧气!

    ④科学家还发现,冬眠不是“习惯养成”的问题,而是遗传基因决定的“天赋”。这种“天赋”还与寿命的长短有联系。一般来讲,哺乳动物的寿命与体型相关,体型小的新陈代谢快,寿命短;体型大的新陈代谢慢,寿命长。比如大象就活80年,兔子七八岁就算高寿。而蝙蝠打破了这个规律——冬眠的菊头蝠和同体型的、不冬眠的老鼠相比,前者可以活到30多岁,后者却只有3、4岁。如果在同一物种中比较,如蝙蝠或者棕熊,依然是冬眠的寿命要长很多。

    ⑤冬眠是当下的热门研究领域。如果人类能像动物们一样冬眠,收获的就绝不仅仅是睡大觉的幸福感,也许还能长生不老。虽然对蝙蝠和棕熊等冬眠动物的研究能确定冬眠基因与长寿有关。但这些动物毕竟与我们人类相差太远。不过,在2004年,有个轰动科学界的发现:居然有一种猴子能冬眠!而人类跟猴子同属灵长类动物,基因相似性很高。如果猴子能冬眠,这意味着我们人类也有可能做到。到那时,我们的寿命说不定可以达到800岁!

(选自《博物》总第146期,有删减)

同类题4

阅读下列短文,从下面每小题的A、B、C、D四个选项中选出最佳选项。

Lee Ming, Ivy, Tony and Terrence are from four different countries. The followings are their diet menus for one day: 

 

breakfast

lunch

dinner

Lee Ming from China

    He eats porridge ( 麦片粥 ). He doesn't like roast bread but he likes Chinese steamed bread. He likes drinking soybean milk.

    He eats rice, chicken, pork and vegetables for lunch.

    He eats the same food as lunch for dinner. After dinner, he will eat some fruit.

Ivy from the USA

    She likes drinking orange juice or coffee. She eats oatmeal (燕麦片) and roast bread for breakfast.

    Her house is far away from her company. So she often has sandwiches, vegetables and soft drinks for lunch.

    After work, she shares a big dinner with her family.

    They will taste steak, beef and seafood. She will enjoy some dessert and some fruit after dinner.

Tony From Britain

    He eats grain with milk and bread for his breakfast. He drinks a cup of orange juice every day.

    He doesn't have much time for lunch. So he often has fast food such as chips, hamburgers, hot dogs and soft drinks.

    He eats beef and chips for dinner. He likes ice cream after dinner.

Terrence from France

    He eats grain products, bread and drinks coffee.

    He likes spaghetti (意大利面条), meat, fish and vegetables for lunch. He drinks some wine during lunch. He has some fruit after lunch.

    He eats soup, ham, cheese, and spaghetti. He drinks some wine as well.