题目

Tong Shiqiang rushed into a kindergarten behind his primary school several times, carrying a __36__ of kids each time he rushed out of their classroom on that fateful（灾难的）day. Only 14 years old and 1.5m tall, Tong can now __37__ a national bravery award for saving seven children. The grade-6 student was __38__ a Chinese language class in Zhongwang Primary School in Qishan village of Longnan city, one of the worst-hit areas in Gansu province, __39__ the deadly quake struck on May 12,2008. There were 49 __40__ students in his class at the time. Windows began rattling(嘎嘎响）and 已知向量a=(4，2)，b=(3，y)，且a⊥b，则y=（　　）A、-6B、6C、-32D、32