What he said was _____ difficult for us _____ understand.     [ ]

A. so; that          

B. very; to        

C. too; to        

D. very; that

超声波雾化吸入后，不需消毒的物品是

A．水槽

B．面罩

C．雾化罐

D．口含嘴

E．螺纹管