Bolts, nuts, split pins, hinges, wheels and stoppers should be frequently （）.A、checkedB、closedC、removedD、cleared

A、Block是HDFS中最小的数据存储单位

B、Split是MapReduce中最小的计算单元

C、Block与Split是一一对应关系

D、Block和Split之间对应关系是任意的，可由用户控制

Adam Smith, a writer in the 1770s, was the first person to see the importance of the division of labor and to explain part of its advantages. He gives as an example the process by which pins were made in England.

"One man draws out the wire, another strengthens it, a third cuts it, a fourth points it, a fifth grinds it at the top to prepare it to receive the head. To make the head requires two or three distinct operations. To put it on is a separate operation, to polish the pins is another. And the important business of making pins is, in this manner, divided into about eighteen distinct operations, which in some factories are all performed by different people, though in others the same man will sometimes perform. two or three of them."

Ten men, Smith said, in this way, turned out twelve pounds of pins a day or about 4 800 pins a piece. But if all of them had worked separately and independently without division of labor, they certainly could not turn out any pin, each of them have made twenty pins in a day and perhaps not even one.

There can be no doubt that division of labor is an efficient way of organizing work. Fewer people can make more pins. Adam Smith saw this but he also took it for granted that division of labor is in itself responsible for economic growth and development and that it accounts for the difference between expanding economies and those that stand still. But division of labor adds nothing new; it only enables people to produce, more of what they already have.

According to the passage, Adam Smith was the first person to______.

A．take advantage of the division of labor

B．explain the causes of the division of labor

C．understand the effects of the division of labor

D．introduce the division of labor into England

A、Of

B、for

C、with

D、in

Adam Smith saw that the division of labor ______.

A．enabled each worker to make pins more quickly and more cheaply

B．increased the number of people employed in factories

C．increased the possible output per worker

D．improved the quality of pins produced