问题 单项选择题

用正循环钻机开孔时,下列操作工序正确的是()。

A.正循环钻机无需泥浆,可直接全速钻孔

B.应慢速推进,待钻头钻进一定深度的土层后,即可全速钻进

C.先钻一定深度的孔,再启动泥浆泵和转盘,待泥浆刚进入孔内,即可慢速钻进

D.应先启动泥浆泵和转盘,待泥浆进入孔内一定数量后,方可开始钻进

答案

参考答案:D

解析:将钻机调平对准钻孔,把钻头吊起徐徐放入护筒内,对正桩位,启动泥浆泵和转盘,等泥浆输到孔内一定数量后,方可开始钻孔。具有导向装置的钻机开钻时,应慢速推进,待导向部位全部钻进土层后,方可全速钻进。正循环钻机开孔时,应先启动泥浆泵和转盘,待泥浆进入孔内一定数量后,方可开始钻进。用泵吸式反循环钻进时,钻头应距孔底20~30cm,防止堵塞吸渣口,在接长钻杆时,应注意接头紧密,防止漏气、漏水和钻杆松脱。

填空题
阅读理解

The discovery of a dwarfed (矮个的)”human being” who lived in Flores .Indonesia, up to 18,000 years ago is changing the way we think about the human family .This “Flores Human”was three foot tall and her brain was smaller than that of the average chimp (黑猩猩),yet she and her relatives apparently lived fully human lives.They seem to have made tools ,worked together to find food and cook it,and perhaps even buried their dead with ceremony.

It was a major surprise to find tools associated with the new human family member .The tools are like those formerly seen only with European fossils (化石)from our own species;Homo sapiens (智人);and the oldest of them were made 94,000 years ago .Homo sapiens is thought to have arrived in the island about 40,000 years ago ,much too late to be responsible for the tools .If this tiny human made the tools ,them the inside structure (结构)of its brain must have been more like our own than a chimp’s ,despite being just a third the size of ours.

This “new human” was suspected to be a dwarfed branch of Homo erectus (直立人).When creatures are separated in regions with rare resources but few enemies,being big is a disadvantage, and evolution tends to shrink them, a process known as island dwarfing.Could natural selection make a human smaller while keeping — even improving — mental ability ?Quite possibly, believes Christopher Wills of the University of California.

Has the “Flores Human” even shown the ability of language? “I find it difficult to imagine that people could make tools,use fire ,and kill large animals without fairly advanced communication.”  Wills says .Did “Flores Human” possess the basic components of human culture — such as the burying of the dead with ceremony ?  Emiliano Bruner of the Italian Institute points out that Indonesia’s hot, wet environment is bad for fossilization.It is reasonable to assume , he says ,that the 18,000-year-old bones of the most complete Flores woman were well-preserved because she was buried with special care.

67.According to the passage , “Flores Human”______.

A.lived a partly human life                        B.was a branch of Homo sapiens

C.used tools before Homo sapiens arrived    D.had a brain as a common chimp’s                    

68.The underlined part “this tiny human”in Paragraph 2 refers to _______.

A.a chimp     .   B.Flores Human C.Homo sapiens   D.Homo erectus                  

69.This passage mainly talks about______.

A.the tools made by “Flores Human”    B.the language used by “Flores Human”

C.the evolution of “Flores Human”             D. the major surprising findings about “Flores Human”      

70.According to the passage ,it is believed that “Flores Human”_______.

A.was dwarfed by its enemies                          B.could use language

C.left a lot of fossils in hot and wet enviroment D.reached Flores 40,000 years ago