近来市场上出现用硫酸铜处理过的“返青粽叶”,食用其包裹的粽子有害健康.硫酸铜属于( )
A.酸
B.碱
C.盐
D.氧化物
答案:C
与牙槽骨垂直吸收有关的是()
A.龈袋
B.骨内袋
C.骨上袋
D.龈沟
E.牙周袋
The guitar must belong _ Jim. He is the only boy to play it here. [ ]
A. to
B. on
C. with