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單項(xiàng)選擇題

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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單項(xiàng)選擇題

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

單項(xiàng)選擇題

“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

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