120．1型控制阀节制阀剩余厚度不足（）时更换。
A.4mm
B.5mm
C.6mm
D.8mm
参考答案：A
China lies the east of Asia and the north of Australia. [ ]
A. to; to
B. in; to
C. to; in
D. in; on
哪个牙的形态不似任何恒牙
A．上颌乳尖牙B．下颌乳尖牙C．上颌乳中切牙D．上颌第二乳磨牙E．下颌第一乳磨牙
