如图所示，用两根长度都为L的细绳，把质量相等、大小相同的a、b两球悬挂于同一高度，静止时两球恰好接触，现把a球拉到细绳处于水平位置，然后由静止释放，当a球摆到最低点与b球相碰后，b球上摆的最大高度不可能为(　　)

完形填空。

     Jean is an English girl. She lives in Beijing 1 her parents. She doesn't know Chinese very 2. But she 3 very hard. She often speaks 4 in class and after class. Sometimes her classmates don't understand her 5 she can't speak Chinese well.

    It's Sunday morning. Jean wants to 6 some flowers, but she doesn't know the 7 to the flower shop. She asks a Chinese boy for help. The boy can't 8 her. Then she takes out a pen and a piece of paper and draws a 9 of a shop and some flowers. The boy looks at it and then 10 her the way.

—Tell us something about Canada, OK?

—I’m sorry. _________ Jack _________ I have ever been there.