题目

选词填空WhySciencesubjectP. E. because （1） I like art it's very exciting. （2） My favorite is music. （3） We can play basketball and volleyball in class. （4） is difficult but it's very interesting. （5） do you like the hamburgers? -Because they're very nice. 答案：【1】because 【1】subject 【1】P. E. 【1】Science 【1】Why某种火药的原料是火硝、木炭和硫黄，它们的比是15：3：2，要制造火药500千克．（1）需要木炭多少千克？（2）木炭比硫磺多多少？（3）火硝比木炭多多少？