Leave him a note at the reception desk,        he will learn how to find you.[ ]

A. which          

B. from which    

C. with which        

D. on which

法兰密封面的不同所采用的垫片不同，通常有以下（）

A.“0”形圈

B.平垫片

C.齿形垫片

D.透气垫片