Choose a fertilizer that contains nitrogen, phosphorus, and potassium.
选择含有氮，磷和钾的肥料。
2
Fertilizer use differs from country to country, and from too little to too much. Nitrogen and phosphorus can produce big crops. But they can also pollute water and air.
肥料的使用因国而异，并且使用的多少也有差别。氮和磷能使作物长得粗壮。但同时也会对水和空气造成污染。
3
Task: Recover phosphorus and nitrogen from wastewater to make fertilizer.