题目内容：

阅读下面短文，在空白处填入1个适当的单词成括号内单词的正确形式。

The burn is a kind of common but very painful 1. (injure), While minor burns will heal without much medical attention, severe burns require special care 2. (prevent) infection. Before you treat a burn, it is important to understand 3. degree of the burn you have suffered.

First degree burns are the most common and happen as a result of brief contact with hot items and the sun. The damage is only 4. the most outer layer of the skin. They will likely appear red and may be 5. (mild) painful.

When you have a second degree burn, your skin might appear 6. (swell), blisters will form and the pain will be math more intense. Second degree burns come from brief contact with extremely hot 7. (thing), extended contact with hot items and long exposure time in the sun.

Third degree burns are the most serious 8. they need immediate medical attention. These happen when extended exposure to a hot object burns through all three layers of your skin, sometimes 9. (cause) muscle, fat and bone damage. The burns will have a white or black 10. (appear). The pain can vary depending on the level of damage to the nerves in the skin layer. These burns can look wet because of the break of the cells.