气性坏疽的主要致病菌为（）.
A.破伤风梭菌
B.产气荚膜梭菌
C.肉毒梭菌
D.艰难梭菌
E.产黑色素普雷沃菌
参考答案：B
Read and judge．(根据课文内容判断，正确的写“√”，错误的写“×"。)
( )1. Sam has got a robot.
( )2, Daming has got a robot.
( )3. Daming's robot can't walk.
( )4. Now, robots can do everything.
( )5. They will do the housework.
( )6. They will help children learn.
隋朝对中国历史有重要的贡献，其中最重要的贡献是（ ）
A．创立了科举制
B．重新统一了中国
C．开通了大运河
D．发展了生产
