單項選擇題
A.8 B.11 C.14 D.16
A.3% B.5% C.7% D.10%
A.5mm B.6mm C.7mm D.8mm
A.5mm B.3mm C.2.5mm D.1.5mm
A.5mm B.3mm C.2mm D.1.5mm
A.20~25mm B.10~20mm C.38~53mm D.65~75mm
A.4~6倍 B.7~8倍 C.2~3倍 D.7.5~8.5倍
A.5mm B.10mm C.15mm D.20mm
A.0.2m B.0.5m C.0.8m D.1m
A.接頭部分的外徑 B.鉆桿本體外徑 C.鉆桿本體內(nèi)徑 D.接頭處內(nèi)徑
A.增強鉆桿的強度 B.增強鉆桿本體與接頭的連接強度 C.提高鉆桿的密封性能 D.增強防斜能力