牙弓后段间隙随年龄增大而增大,女性在14岁前,男性在16岁前,每年每侧平均增大()
A.0.5mm
B.1.5mm
C.2.5mm
D.3mm
E.3.5mm
参考答案:B
. He is rather difficult to makefriends with, but his friendship, ____, ismore true than
anyother.
A.once gained
B.when to gain
C.after is gained
D.while gaining
按石料形状分为料石、块石、卵石三大类。