例句與造句

1. In 1939, after working as a Sales Engineer with Reed Roller Bit Company in fracturing and cementing.
2. It is unlikely that he actually invented the two-cone roller bit, but his legal experience helped him in understanding that its patents were important for capitalizing on the invention.
3. In the 1970s, outside of the oil and gas industry, roller bits using mud circulation were replaced by the first pneumatic reciprocating piston Reverse Circulation ( RC ) drills, and became essentially obsolete for most shallow drilling, and are now only used in certain situations where rocks preclude other methods.
4. It's difficult to find roller bits in a sentence. 用roller bits造句挺難的