It is not so much the possible trouble caused by helping others _______ people’s unwillingness to show their sympathy _________ accounts for the present situation.

A．as; as

B．as; that

C．that; which

D．that; as

俗话说“食不言，寝不语”。吃饭时不能大声谈笑是有科学道理的，原因是 [ ]

A．不利于食物消化                    

B．食物容易由咽误入气管  

C．唾液腺分泌唾液的量减少            

D．有利于保护声带