学习一门外语是非常重要的.(It's…to…)
Hold on to your (梦想), and one day it may come true.
When we left, the kids said goodbye to us (礼貌).
The stamp I bought yesterday (花费)me 20 yuan.
It's a good habit to brush your (牙齿) after a meal.
People often fly kites on sunny and (多风)days.