语法填空
阅读下面材料，在空格处填入适当的内容（不多于3个单词）或使用括号中单词的正确形式。
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       (excite) I was when I saw the bike, and I begged my uncle to teach me how     (ride) it right away. However, before I got on the bike, I felt     (extreme) nervous and I was afraid that I would fall off and hurt     (me). My uncle held onto the seat and helped me to get      the bike. While I was riding, he was running along beside me, holding the seat so I would not fall over. I was so     (grate) to him for his help.
As I was practicing, I became more and more confident. Then, I heard my uncle shouting, “You are riding it by yourself now!” I was both excited and scared. I was really riding by myself, but    if I fell off? Could I use the brakes to stop? As I was wondering about this, my uncle ran after me and got hold of the bike. I      (slow) down and came to a stop. My heart was still beating fast when I got off the bike.       (late) that day, having learnt how to get on the bike and get off it, I felt like I was walking on air! I am still thankful to my uncle for teaching me to ride a bike on my       (nine) birthday.