单项选择题
A device used to enlarge the size of an existing bore hole，having teeth arranged on its outside circumference to cut the formation as it rotates is a（n）（）.
A.Enlarger bit
B.Casing bit
C.Hole opener
D.Casing opener
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相关考题
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单项选择题
A “figure eight” knot is used to（）.
A.be a stopper
B.shorten a line
C.join lines of equal size
D.keep a line from passing through a sheave -
单项选择题
“15 02 41 Semi Double Queen 195 332mm”is a description of（）.
A.ISSA stores
B.IMPA stores
C.common marine stores
D.a reference to be studied -
单项选择题
（） is true.
A.ISSA stores are numbered in six digits
B.IMPA stores are numbered in six digits
C.IMPA stores are numbered in seven digits
D.both ISSA and IMPA stores are numbered in unique six digits
