题目

Driving on up to Yosemite with my family was exciting but nerve-racking (神经紧张的). I had never been to such an amazing national park before, yet I wasn’t the most athletic person so I knew that I couldn’t stick through all the hiking up and down. It actually ended up being a fun and adventurous experience. The ride there was definitely long but worth it. As I woke up from my nap, I saw the beautiful scenery of the tall mountains and beautiful streams. The trails were made nicely for visitors. The waterfalls were breathtaking. Climbing up rocks was one of my favorite parts. 下列物质中含有自由移动Cl-的是    A．氯酸钾固体      B．液氯              C．氯化氢气体        D．氯化钾溶液