30．It is reported that there will be a heavy rain tomorrow; _____ the hike would be put off．

A．in any case

B．in which case

C．in this case

D．in no case

机体天然预防尿路感染的屏障作用有()

A．尿路冲刷作用

B．尿路粘膜分泌作用

C．尿路环境一般呈碱性状态

D．尿液中含有某些抗菌物质

E．尿路环境呈酸性