Ⅰ度松动的牙松动方向是（）

A.仅有唇（颊）舌向松动

B.唇（颊）舌向及近远中向均有松动

C.近远中向及垂直向均有松动

D.唇（颊）舌向及近远中向松动，并伴有垂直向松动

E.以上均不对

When hanging off drill pipe in emergency situations aboard a ship，the preferred location of the drill bit is（）.

A.on bottom with the full drill string in tension

B.one stand (approximately 93 feet) off bottom

C.no deeper than the shoe of the last casing set

D.as close to the surface as possible