题型：问答题 The number of people in the world _____ about 6 billion and large quantities of waste _____ each year.A. total; has been produced B. totals; is produced C. totals; are produced D. total; are being produced 查看答案
题型：问答题 初三化学兴趣小组用实验证明鸡蛋壳的主要成分是碳酸盐，请帮他们完成下列实验报告．（实验目的、实验结论略） 实验用品 实 验 步 骤 实验现象 （1）试管 带导管的单孔塞铁架台（2）碎鸡蛋壳 稀盐酸 澄清石灰水（1）将碎鸡蛋壳______（2）______（1）______（2）______ 查看答案