-- Hello, this is Jack. Mary I speak to Tom?

--  Sorry,  he isn't in at the moment.  If he        back, I'II  ask him to call you back.

A．come

B．comes

C．have come

D．came

内斜切口的优点是（）

A.直接切除袋内壁上皮和炎症组织

B.保留牙周袋表面的附着龈

C.术后牙龈退缩少

D.愈合后牙龈外形较好

E.以上都是