题目

根据句意及首字母提示完成单词（1）My father usually c my homework at home.（2）, Tom cleans the classroom and goes home.（3）You can c “save”, and then write a name for it.（4）Can you see the train t on the wall?（5）I often go to Beijing by t. 答案：【1】checks【2】Finally【3】click【4】timetable【5】train下列有关说法正确的是 A．空气由氧气和氮气组成，其中氧气的质量约占空气质量的1／5B．带火星的木条一定能在含有氧气的集气瓶中复燃 C．将燃着的木条伸入集气瓶，火焰立即熄灭，证明瓶内原有气体就是二氧化碳D．锅炉中使用硬水容易产生水垢，严重时会引起爆炸