下列各数中,小于-3的数是 A.2 B.1 C.-2 D.-4

题型:选择题

问题:

下列各数中,小于-3的数是

A.2

B.1

C.-2

D.-4

考点:有理数定义及分类正数与负数数轴相反数
题型:选择题

Frogs are animals that can live both in water and on land. There are more than 5,000 kinds of frogs on the earth. The earliest known frogs lived about 190 million years ago and the frogs today still look the same. Here are some fun things that you might not know about frogs. Enjoy!

The Biggest and the Smallest Frogs

Some frogs can be very big. The biggest kind of frog is the Goliath Frog in West Africa. Its body can be nearly 30cm long, about the size of a large cat. The Gold Frog and the Poison Frog are the smallest frogs in the world. They are less than 1cm long. Though the Poison Frog is very small, it is not weak at all. It is dangerous. Any animal that eats it will die very soon.

The Best Jumpers

Frogs are very good at jumping. They developed jumping legs so that they would not be eaten by other large animals. Using their big strong legs, more frogs can jump over 20 times their own length. The Australian Rocket Frog can even jump over 2m, which is 50 times its body length (5.5 cm). That might be the reason why frogs are called the best jumpers on the earth.

The Cryogenic Animal

Some frogs like the Common Wood Frog have a special ability to live in very cold places. When the temperature goes down, they become ice frogs. 2/3of their body water freezes. Their hearts stop, and their breathing stops too. You may think they are dead, but in fact they are not. Maybe we humans can learn the way that the frogs do for medical purpose.

小题1:The earliest frogs lived about          million years ago.

A.20

B.30

C.50

D.190小题2:      can jump over 2m.

A.The Goliath Frog

B.The Common Wood Frog

C.The Poison Frog

D.The Australian Rocket Frog小题3:What will happen to a Common Wood Frog at very low temperature?

A.It will die very soon.

B.It will be an ice frog.

C.It will become dangerous.

D.It will become very small.

题型:选择题

油墨能牢固的附着在纸张表面的原因:1、()2、当油墨转移到纸张上以后,有明显的机械投锚效应3、纸张为高能表面,油墨的表面张力很低,比表面能高的表面,很容易被表面张力低的液体润湿。

题型:选择题

计划的主要原因是()

A.满足员工的需求

B.环境的不确定性

C.竞争的需要

D.组织政策

题型:选择题

对于根挺的使用,错误的操作是()。

A.当断根的断面为斜面时,根挺应从斜面较高的一侧插入

B.根挺用力时,其支点应在唇颊侧牙槽骨板,而不是邻牙

C.拔上颌断根时,根挺的插入方向应与根长轴平行

D.拔除断根时,根挺的用力方向应与牙根成30°~80°角

E.使用根挺时,旋转的频度要高,旋转的角度要小

题型:选择题

步行几乎适合于每一个进行健身运动的人。

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