第三节 语法填空 (共10小题；每小题1 分；满分10分)
It is important for you to learn some knowledge about first aid in your daily life. If a person has __51__ accident he needs medical care __52__ a doctor can be found. When you give first aid, you must pay attention to three things. First, when a person stops breathing, open his /her mouth and see __53__ there is food at the back of his / her mouth.
