题干

蝙蝠不属于鸟类,而属于哺乳类,这是因为其(  )

A:有发达的胸肌

B:善于飞翔

C:是胎生哺乳

D:有翼

上一题 下一题 0.0难度 选择题 更新时间:2018-11-24 09:17:25

答案(点此获取答案解析)

C

同类题3

阅读下面的短文用英语回答问题,并将答案写在横线上。

    It was a summer afternoon in the countryside. Wan Bo, a university student, was painting while his classmate Tang Qi was making a wooden box by the river. A little riding on a rocking horse caught their eye by chance. It brought them back to their childhood, warm and happy.

    "Why not try to make one by ourselves?" said Wan Bo. "You are good at making things and I am interested in painting."

    "Actions speak louder than words," Tang Qi said. Then, the two young men began to collect some information about it. During those days, watching videos about caring(雕刻) and shaping wood into horse shapes on the Internet became an important part of their life.

    Several months later, a wooden rocking horse appeared. They felt so excited that they put the picture of it on the Internet right away. To their surprise, it attracted lots of people's attention and some even hoped to order one.

    The two young men thought it might be a good chance. They sent some forms to the customers to make a survey. According to the result, they made each customer a special rocking horse. These horses were quite different from those produced in other factories, and they soon became popular among the customers.

    In the first year of their new hobby, Wan and Tang made thirteen rocking horses. Sometimes, they also repaired rocking horses for people. They made the old ones look new again. Wan and Tang helped those people bring back many happy memories.

    Their hobby has now become a successful and busy business.

同类题5

阅读《苍蝇可能感觉自己活了很久》  ,回答相关问题
                                                                                     苍蝇可能感觉自己活了很久
        ①苍蝇的寿命比大象短,这是毫无疑问的。但是,假如苍蝇对时间有感觉,它真的感到自己的生命那么短暂吗?
        ②地球上的生物,对时间的感知是由神经传导的快慢决定的,也可以说每个生物个体对时间的感知是不同的。最新的研究显示,体积愈小的动物,新陈代谢率愈快,时间过得愈慢。这意味着小动物比大动物更能在极短时间内观察到动态行为,它们眼中的世界就像慢动作回放。譬如昆虫和小鸟,它们在1秒钟所看到的信息,要比诸如大象等大动物看到的更多。
        ③研究人员利用“临界闪光融合频率”的技术,来测量不同动物的眼睛处理闪光的速度。这项技术简称为CFF,它提供了一种感知时间的方法。【甲】它由快速闪耀的闪光点组成,看起来像一个连续光源。被测试个体如果能识别出个别的闪光,那么时间对它而言流动就较慢。通过对测量数据的分析,研究人员发现,躯体的大小与眼睛对视觉信息反应的速度之间,有非常紧密的关系。体积愈小的动物,看到的世界就愈“慢动作”。【乙】对人类来说,平均的CFF是60赫兹(即每秒60次),这是通常设置的电视图像的刷新率。狗眼睛的刷新率是80赫兹,对狗来说,电视图像看起来像一系列快速变化的幻灯片。【丙】苍蝇的CFF是250赫兹,这就是说苍蝇眼睛对刺激动作的反应,比人类的眼睛快4倍以上,所以苍蝇很难被拍死,因为在人类看来迅速落下的一卷报纸,在苍蝇的眼中就像是慢动作。
        ④大象能活60年,但是它们的生活节奏比苍蝇慢几十倍。对大象来说,一天的时间很快就过去了;而对苍蝇而言,一天的时间过得很慢。苍蝇对人类来说是很短命,但是从苍蝇的角度来说,它们可能活了很长。