皮皮学,免费搜题
登录
logo - 刷刷题
搜题
【简答题】
It's important to learn how we can protect the environment . Here are 5R rules for us . Reduce( 减少 ) . If you want to reduce waste, you should use things more cleverly . A large number of trees are being cut down to make paper . If everyone uses paper carelessly, soon we would not have any trees left . Other things are also being wasted, and people don't know what to do with the waste in big cities . So it is necessary to reduce the amount( 数量 )of waste we produce . Reuse . You should always think of reusing things before throwing them out . For example, give the clothes you do not use or the ones that are too small to the poor . In a family, you may pass on such clothes to younger brothers or sisters . Recycle . Bottles, cans and paper can easily be recycled . By doing so we save lots of time and money . For example, coke cans are sent to a factory, where they are smashed flat and melted . The metal can be used to make new coke cans . Recover . When you buy a box of apples, there may be a few rotten( 腐烂的 )ones . You have two choices : one is to throw the apples away; the second is to throw the rotten ones and keep the good ones . In this way, you are recovering the eatable parts of food . Repair . If one of the legs of your table is broken, you should repair it . If you want to buy something newer and better, it is better for you to sell the old thing, or give it to people who can use it after repairing it . Learn the rules to protect our environment . Let's try our best to make the earth cleaner and more beautiful .
手机使用
分享
复制链接
新浪微博
分享QQ
微信扫一扫
微信内点击右上角“…”即可分享
反馈
参考答案:
举一反三
【判断题】大小相等、方向相反、作用在同一刚体上的两个力一定平衡
A.
正确
B.
错误
【判断题】凸轮机构常用滚子从动件,由于它在工作中的摩擦阻力小,不易磨损,所以特别适用于高速场合
A.
正确
B.
错误
【简答题】三料是指什么?
【判断题】带有螺纹的塑件,要求在成型后自动卸螺纹时,模具中设置固定的螺纹型芯或型环,利用注射机本身的旋转运动或往复运动,将螺纹塑件脱出。
A.
正确
B.
错误
【单选题】2-9 下图六角砚台三维模型中内凹的圆孔是()几何体创建的。
A.
环棱柱
B.
四棱柱
C.
圆柱
D.
切角圆柱体
【单选题】2-9 下图六角砚台三维模型中内凹的圆孔是()几何体创建的。
A.
环棱柱
B.
四棱柱
C.
圆柱
D.
切角圆柱体
【判断题】凸轮机构中,尖顶从动件比滚子从动件更适合高速。
A.
正确
B.
错误
【判断题】凸轮机构常用滚子从动件,由于它在工作中的摩擦阻力小,不易摩擦,所以特别适用高速场合。
A.
正确
B.
错误
【单选题】凸轮机构中,滚子从动件适合于
A.
只用于低速重载场合
B.
耐磨损、可承受较大载荷,应用最为广泛
C.
只适用于高速重载场合
D.
只用于中速重载场合
【判断题】带有螺纹的塑件,要求在成型后自动卸螺纹时,模具中设置固定的螺纹型芯或型环,利用注射机本身的旋转运动或往复运动,将螺纹塑件脱出。
A.
正确
B.
错误
相关题目:
参考解析:
知识点:
题目纠错 0
发布
创建自己的小题库 - 刷刷题