问题
选择题
It's ______ black. It's ______ black ruler. [ ]
A. a; /
B. /; a
C. a; a
D. /; /
答案
答案：B
搜题请搜索小程序“爱下问搜题”
It's ______ black. It's ______ black ruler. [ ]
A. a; /
B. /; a
C. a; a
D. /; /
答案：B
的牙周膜、牙槽骨及唇侧龈的神经是（）