设$a={\log }_{\frac{1}{2}}3,b={\left(\frac{1}{3}\right)}^{0.2},c=2^{\frac{1}{3}}$，则（   ）

2015年4月25日14时11分，尼泊尔（位于中国与印度之间）发生里氏8．1级地震，余震100多次，造成大量人员伤亡和财产损失，据此回答下列各题。

    It's seven forty in the morning. The children are coming into the classroom. A girl is opening the windows. Some are laughing and talking. Some are listening to them. Some are reading books. Some are doing their homework.

    Miss Gao is standing behind the teacher's desk. She is writing on the blackboard. Sue and Han Mei are wearing their new dresses today. Ann is cleaning her desk. Mike is helping her. They all look happy.

What are Bill and Lin Tao doing? Oh, dear! They are still playing basketball!