Many people like the gigantic whales. Human sympathy 【C1】______ whales is only natural of all the creatures in the sea. 【C2】______ are closer relatives to us than these warm-blooded mammals. And how they got into the sea is one of the most fascinating stories of 【C3】______ . Most authorities believe that 60 million years ago ancestors of modern whales were four-legged, wolf-size animals living on the sea shores, 【C4】______ an abundance of fish and shrimp tempted them to try wading. Over 10 to 15 million years, their bodies grew, forelegs shrank into flippers used for 【C5】______ and steering and hind legs disappeared. As a result of some amazing transformations, they arc now helpless on land. If stranded on a beach, they can barely breathe.
With abundant 【C6】______ of food, whales grew into the largest creatures that lived, 【C7】______ larger than dinosaurs. A blue whale can grow to 100 feet. Its tongue is ten feet thick and heavier than an elephant. Some arteries are big enough for a child to swim 【C8】______ . The half-ton heart has walls two feet thick and pumps eight tons of blood. 【C9】______ its size comes awesome strength. A blue whale swimming 【C10】______ 15 knots generates 1000 horsepower. 【C11】______ their size, these giants move at a good speed. An 18-ton whale can even 【C12】______ 12 m. p. h., over short distances. A whale can 【C13】______ up to 9000 pounds of food a day. The world's biggest creature 【C14】______ itself almost entirely on shrimp-like krill, smaller than a person's thumb.
Maternal instincts are also highly 【C15】______ . Because a calf is born underwater, the mother must get it to the surface before it 【C16】______ . Often another whale will help. The mother pushes it gently 【C17】______ the baby is confident with its swimming usually after about 30 minutes. If the calf is born 【C18】______ , she may support it on her back until it gradually rots away. Like all mammals, whale babies feed 【C19】______ mother's milk. And the milk is more than 30-percent fat, over 10-percent protein, and the babies grow extremely fast. A blue whale calf lengthens 【C20】______ two inches a day and gains an average seven pounds per hour.
【C1】
A.with
B.to
C.for
D.in
第1题
A.使用电话网接入Internet时,需要使用Modem
B.ADSL和ISDN一样,上网和打电话可以同时进行
C.ISDN的下载速度比上传速度快
D.利用有线电视网接入Internet时,需要用到一种专门的Modem
第2题
(59)下面关于局域网接入 Internet的叙述中,错误的是
A)局域网接入 Internet时,通常需要使用路由器
B)每个以太网卡有一个全球准一的 MAC 地址
C)PC可以使用非屏蔽双绞线连接到集线器或交换机
D)局域网中交换机的主要功能是用于扩大网络传输距离
第3题
A.ADSL是一种非对称传输模式,其数据上传速度比下载速度快
B.使用ADSL接入Internet时,PC机中需要安装网卡
C.ADSL和ISDN接入方式一样,可以同时上网和打电话
D.ADSL和电话拨号接入方式相仿,但使用的MODEM不同
第4题
下面关于局域网接入Internet的叙述中,错误的是
A.局域网接入Internet时,通常需要使用路由器
B.每个以太网卡有一个全球准一的MAC地址
C.PC可以使用非屏蔽双绞线连接到集线器或交换机
D.局域网中交换机的主要功能是用于扩大网络传输距离
第5题
下面关于局域网接入Internet的叙述中,错误的是
A.局域网接入Internet时,通常需要使用路由器
B.每个以太网卡有一个全球准一的MAC地址
C.PC可以使用非屏蔽双绞线连接到集线器或交换机
D.局域网中交换机的主要功能是用于扩大网络传输距离
第8题
将局域网接入Internet所需使用的接入设备是()。
A)电话网
B)路由器
C)集线器
D)中继转发器
第9题
将局域网接入Internet所需使用的接入设备是()。
A)电话网
B)路由器
C)集线器
D)中继转发器
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