每天坚持背默！
The deepest holes all are made for oil,and they go down to as much as 25,000feet ,but we do not need to send men down to get the oil out,as we must with any other mineral deposits .The holes are only borings,less than a foot in diameter.My particular experience is largely in oil,and the search for oil has done more to improve deep drilling than any other mining activity.When it has been decided where we are going to drill,we put up at the surface an oil derrick,which has to be tall bacause it is like a giant block and tackle.（And）We（have to） lower it into the ground and haul out of the ground great length（lengths） of drill pipe which is （are）rotated by an engine at the top and are fitting（fitted） with a cutting bit at the bottom.
The geologist needs to know what rocks the drill has reached,so every so often a sample is obtained with a coring bit.It cuts a clean cylinda of rock ,from which can be seen the strata the drill has been cutting through.Once we get down to the oil,it ususally flows out to the surface because great pressure,either from gas or water,is pushing it.This pressure must be under contral（control）,and we contral（control）it by the means of mud which we circulate down the drill pipe.We endeavor（endeavour） not to use（avoid） the old ,romantic idea of gusher,which wastes oil and gas.We want it to stay down the hole until we can lead it off in a contraled （controlled）manner.
