启动水解输料风机后，测试风机取风口无风，则可判断风机内被物料堵塞。
参考答案：对
These shoes look very good. I wonder __________.
A．how much cost they are
B．how much do they cost
C．how much they cost
D．how much are they cost
何种细菌污染了化妆品会引起角膜的化脓性溃疡（）。
A.金黄色葡萄球菌
B.绿脓杆菌
C.幽门螺杆菌
D.大肠杆菌
E.粪大肠杆菌
