缓冲区不应设置在（）或不作单独设计的桥上。
A、道岔两端
B、道口
C、直线上
D、曲线上
参考答案：B
My mother asked you _______ when you come back.[ ]
A. ring up her
B. ring her up
C. to ring up her
D. to ring her up
产气荚膜梭菌菌体呈（）
A.汤匙状
B.鼓槌状
C.竹节状
D.椭圆形
E.棒状
