题目

I was nine years old when I learnt to ride a bike. The bike was a birthday present from my uncle. You can imagine how    61    (excite)I was when I saw the bike, and I begged my uncle to teach me how    62   (ride) it right away. However, before I got on the bike, I felt      63    (extreme) nervous and l was afraid that l would fall off and hurt    64   (me). My uncle held onto the seat and helped me to get    65    the bike. While l was riding, he was running along beside me, holding the seat so I would not fall over .I was so    66   (grate) to hi为了除去一氧化碳中混有的少量氧气，某同学设计了右图所示的这套装置（装置气密性良好）．（1）他想用这套装置除去氧气的化学方程式是：    ；（2）老师认为他的实验设计不科学，请你指出存在的错误（任写一点）：    ．