A burn is an injury to the skin caused by exposure to fire, hot liquids or metals, chemicals, electricity or the sun‘s ultraviolet rays. When someone gets a burn , it‘s necessary to provide first - aid right away. First aid for burns involves removing the source of the burn as soon as possible. The burns should be cooled immediately with cold water. A clean, cold wet towel or dressing can be placed on less serious burns to ease pain and protect the burns from contaminating. If the burn is caused by chemicals, it should be bathed continuously with running water for at least 20 minutes to reduce the substance. Any powder should be carefully brushed off with gloved or protected hands before washing. Wet dressings should never be used for burns. Instead, the first - aid provider should gently apply dry, sterile dressing held in place by bandages and seek immediate medical attention.

Our future house will be on the ocean. It will be surrounded by tall trees and blue sea. But we only have salt water in the ocean. We needs fresh water for (26) and for growing food (27) farms.
Ocean water is too salty (28) . It is also too salty for watering plants. We must have the (29) to make fresh water from salty water. We should be (30) not to waste water.