二氧化氯杀生剂在PH=（）范围内最有效。 A.6—10 B.7.0—9.2
题型：单项选择题
问题：
二氧化氯杀生剂在PH=（）范围内最有效。
A.6—10
B.7.0—9.2
题型：单项选择题
| 阅读下面短文，请从方框中选出适当的句子填入文中的适当位置，使短文内容完整正确。 |
| Tai chi is also popular in the world. He watched a fight between a snake and an eagle. Tai chi has a very long history. Fans from around the world will enjoy the show. Its basic idea is the soft overcoming the hard (以柔克刚). |