将氧化铜和氧化镁分别放入足量的稀硫酸中，当生成等质量的水时，需要消耗氧化铜和氧化镁的质量比为　____ ，这些参加反应的氧化物中，铜、镁元素的质量比是____ 。

     A woman is having some trouble(患病) with her eyes, so she goes to see the doctor. He is a new doctor and doesn’t know her, so he asks some questions and one of them is, “How old are you?”

     The woman says, “I don’t know, doctor, but let me think about it.” She thinks for a few minutes and then says, “Yes, I know now, doctor! When I marry(结婚), I am eighteen years old, and my husband is thirty. Now my husband is sixty. And that is twice(两倍) thirty. So I am twice eighteen. That’s thirty-six, isn’t it?”

We're writing                  you about                  wild animals.

人们常用“七分海洋、三分陆地”粗略地说明全球海洋和陆地面积的比例。但我们还是习惯称居住的星球叫地球，你认为理由应该是（    ）