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Why should we sort our garbage? The answer lies in the increasing amount of waste we are producing. Chinese cities produce over 200 1． tons of waste each year, according to China Economic Net. Most of this waste is buried(填埋) in landfills(垃圾填埋场), which may pollute water and soil. What’s more, we are running out of space for new landfills.
In fact, more than half of our waste can be recycled. Recyclable garbage can be made into something 2．, while wet garbage can be used to make gas, heat and fertilizer (肥料).So we need to sort our garbage.
Can’t garbage-processing companies do the sorting job for us? They can. But that requires a lot of 3． and costs lots of money. Things will become much 4． if each of us can sort our own garbage. Also, the task of sorting encourage people 5． less waste.
同类型试题
y = sin x， x∈R， y∈[–1，1]，周期为2π，函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x， x∈[–1，1]， y∈[–π/2，π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2
y = sin x， x∈R， y∈[–1，1]，周期为2π，函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x， x∈[–1，1]， y∈[–π/2，π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2
