Read and fill in the blanks. (根据汉语提示补全句子)

1. It's the ____ of the school year. We're going to have a party. (结束, 末尾)

2. I don't ____ to say goodbye to my friends. (想)

3. I hope you will get better ____. (不久)

4. ____ be sad. We will give you a surprise. (不要)

5. He's _____ China. He's tall. (来自)

维持人工游泳池水的透明度，最简单的方式是（）。