A.4B.3C.2D.1
A.單點(diǎn)儀器B.多點(diǎn)儀器C.隨鉆儀器D.以上三項(xiàng)都對(duì)
A.增大無(wú)磁鉆鋌的長(zhǎng)度B.減小無(wú)磁鉆鋌長(zhǎng)度C.增大地磁磁性D.減小地磁磁性