题目

阅读短文，根据短文内容回答问题。Last holiday, I took a big trip with my aunt. We went to Australia by plane. It was in August. We left Beijing on Aug 3rd. It was winter in Australia. But in Beijing, it was summer. I like there, because I like playing with snow. I went ice-skating there and took many pictures. I bought many presents for my friends, too. I was excited, but I was tired, too. I should relax to go back to school.【1】Who went on a big trip?__________________________________________【2】When was my big trip?__________________________________________【3】What di鉴别三个集气瓶中的无色气体分别是空气、氧气和二氧化碳，最简单的方法是     A. 分别测定气体的密度                   B. 分别加入澄清石灰水     C.将燃着的木条分别伸入集气瓶中  D. 分别加入水