乳牙中最早脱落的是()
A.上颌乳中切牙
B.下颌乳中切牙
C.上颌乳侧切牙
D.下颌乳侧切牙
E.下颌乳尖牙
参考答案:B
按比例绘制的通风系统图是()
A、矿井通风系统工程图
B、矿井通风系统平面示意图
C、矿井通风系统立体示意图
D、矿井通风网路图
There()in that part of the country.
A.are not much industry
B.is not many industry
C.are not many industry
D.is not much industry