以下哪些危害因素导致的食物中毒有较高的死亡率？（）
A.肉毒梭菌
B.雪卡毒素
C.贝类毒素
D.野蘑菇
参考答案：A, C, D
热应力指数用于（）环境
A、湿
B、寒冷
C、热
D、干燥
The US first lady Michelle Obama gave speeches in Beijing University, which Chinese students’ heated discussions about going abroad for further study.
A．turn on
B．go down
C．set off
D．come up
