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Cost as a Factor in SupplyIn a purely competitive market, the supplier of goods and services has no control over the market price, because he produces too little to influence market conditions. With no difference between his products and the products (51) his competitors, he will sell nothing if he charges above the market price and he will sell all if he charges at or (52) the market price. However, in considering the price, he must take the (53) of production into consideration. There are times when he may be willing to sell below his cost. This might happen when prices tumble for (54) he believes will be a short time. However, no business person can (55) to lose money for a prolonged period. He must be constantly (56) of his costs in relation to the market price if he is to compete successfully and earn a profit.Many people have the impression that as production increases, costs per unit decrease. (57) mass production has made this true in certain industries and at certain levels of production, (58) logic and practical experiences have shown that costs per unit begin to rise beyond a certain level of production. Some economists (59) to this principle as the law of increasing costs.The reason costs rise as production goes up is (60) . However, it is easy to recognize that as production goes up, the need for additional factors of production will also grow, (61) competitive bidding in the marketplace for the factors of production. If a producer needs (62) skilled labor to produce more, and none of this labor is unemployed, the producer will have to get (63) from other sources. This can be done by (64) higher wages. Higher bidding would also apply to the other factors of production. We must also recognize that not all labor is equally productive, (65) not all land is equally fertile and not all ore (矿石) is equally rich in the mineral wanted. 63().

A. them
B. these
C. it
D. those

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In the second half of each year, many powerful storms are born in the tropical Atlantic and Caribbean seas. Of (91) , only about half a dozen (92) the strong, circling winds of 75 miles per hour or more that give them hurricane status, and several usually (93) their way to the coast. There cause millions of dollars of (94) , and bring death to (95) numbers of people. The great storms that hit the coast start (96) innocent circling disturbances hundreds, even thousands of miles out to sea. As they travel aimlessly over water (97) by the summer sun, they are carried westward by the (98) winds. When conditions are just (99) , warm, moist air flows in (100) the bottom of such a disturbance, moves upward through it and comes out at the top. In the (101) , the moisture in this warm air produces rain, and with it the heat is converted to energy in the form of strong winds. As the heat increases, the (102) hurricane begins to swirl in a counter-clockwise motion. The average life of a hurricane is only about nine days, but it contains almost (103) power than we can imagine. The energy in the heat released by a hurricane’s rainfall in a(n) (104) day would (105) the entire electrical needs of the United States for more than six months. Water, not wind, is the main (106) of death and destruction in a hurricane. A(n) (107) hurricane brings 6-to 12-inch downpours (108) in sudden floods. (109) is the powerful movement of the sea-the mountains of water moving toward the low-pressure hurricane center. The water level (110) as much as 15 feet above normal as it moves toward shore.

A. as
B. with
C. from
D. at

制剂的含量测定应首选色谱法,应用率最高的是

A. HPLC
B. UV
C. TLC
D. IR
E. GC

适用于氨基酸蛋白质及带电离子的分离定量方法是

A. HPLC
B. 旋光测定法
C. 容量分析法
D. 重量法
E. 电泳法

The Cold Places The Arctic is a polar region. It surrounds the North Pole. Like Antarctica, the Arctic is a land of ice and snow. Antarctica holds the record for a low temperature reading—125 Fahrenheit below zero. Readings of 85 degrees below zero are common in both the Arctic and Antarctica. Winter temperatures average 30 degrees below zero in the Arctic. At the South Pole the winter is about 73 degrees below zero. One thing alone makes it almost impossible for men to Jive in Antarctica and in parts of the Arctic. This one thing is the low temperature—the killing chili of the far North and the polar South. To survive, men must wear the warmest possible clothing. They must build windproof shelters. They must keep heaters going at all times. Not even for moment can they be unprotected against the below-zero temperature. Men have a way of providing for themselves. Polar explorers wrap themselves in warm coats and furs. The cold makes life difficult. But the explorers can stay alive. What about animals Can they survive Do we find plants Do we find life in the Arctic and the Antarctica Yes, we do. There is life in the oceans. There is life on land. Antarctica, as we have seen, is a cold place indeed. But this has not always been the case. Expedition scientists have discovered that Antarctica may have been much like our own. Explores have discovered coal in Antarctica. This leads them to believe that Antarctica at one time was a land of swamps and forests. Heat and moisture must have kept the trees in the forests alive. As discovered by expedition scientists, Antarctica has not always been so cold as it is today, so has the Arctic.

A. Right
B. Wrong
C. Not mentioned

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