阅读下面材料，在空白处填入适当的内容（1个单词）或括号内单词的正确形式。
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 andhelped me to get ____the bike. While I was riding, he wasrunning 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, Iheard my uncle shouting, “You are riding it by yourself now!” I was bothexcited and scared. I was really riding by myself, but ____if I fell off? Could I use the brakesto stop? As I was wondering about this, my uncle ran after me and got hold ofthe bike. I ____(slow) down and came to a stop. Myheart was still beating fast when I got off the bike. ____ (late) that day, having learnt how to get onthe bike and get off it, I felt like I was walking on air! I am still thankfulto my uncle for teaching me to ride a bike on my ____ (nine) birthday.
，
，
，
，
，
， 
.单项式的共有（ ）
，
，则
=（ ）
