正常情况下，混合静脉血氧饱和度为（） A.90% B.85% C.75% D.70%

读“澳大利亚气候分布图”，回答下列问题．

（1）写出图中代号所代表的气候类型名称：

①______，②______，③______，④______，⑤______，⑥______．

（2）南回归线横穿澳大利亚大陆的______部，因而______带气候分布广．

（3）澳大利亚大陆就东西半球而言，位于______半球，就南北半球而言位于______半球．

CT检查中，图像重组（Refomaticn）与图像重建（Reconstnction）的主要区别是（）

A、重建使用无间隔的原始数据，重组使用一定间隔的原始数据。

B、重建通过原始数据得到显示数据图像，重组通过显示数据得到新层面的图像。

C、重建出的图像质量不如重组得出的图像。

D、原始横断面的层厚对重组图像的质量影响较小。

E、图像重组比图像重建损失的诊断信息少。

下列那些是集气站防止水合物生产的方法（）。

A.加注甲醇

B.加热炉

C.缓蚀剂

D.A和B

计算题：一台阳离子交换器直径D=2.5m，再生一次需浓度为31%的工业盐酸1065L，再生时，盐酸浓度为3%，再生流速v=5m/h，求进酸时间。

If there is one thing scientists have to hear, it is that the game is over. Raised on the belief of an endless voyage of discovery, they recoil from the suggestion that most of the best things have already been located. If they have, today’s scientists can hope to contribute no more than a few grace notes to the symphony of science.

A book to be published in Britain this week, The End of Science, argues persuasively that this is the case. Its author, John Horgan, is a senior writer for Scientific American magazine, who has interviewed many of today’s leading scientists and science philosophers. The shock of realizing that science might be over came to him, he says, when he was talking to Oxford mathematician and physicist Sir Roger Penrose.

The End of Science provoked a wave of denunciation in the United States last year. "The reaction has been one of complete shock and disbelief, "Mr. Horgan says.

The real question is whether any remaining unsolved problems, of which there are plenty, lend themselves to universal solutions. If they do not, then the focus of scientific discovery is already narrowing. Since the triumphs of the 1960s—the genetic code, plate tectonics, and the microwave background radiation that went a long way towards proving the Big Bang—genuine scientific revolutions have been scarce. More scientists are now alive, spending more money on research, that ever. Yet most of the great discoveries of the 19th and 20th centuries were made before the appearance of state sponsorship, when the scientific enterprise was a fraction of its present size.

Were the scientists who made these discoveries brighter than today’s That seems unlikely. A far more reasonable explanation is that fundamental science has already entered a period of diminished returns. "Look, don’t get me wrong," says Mr Horgan. "There are lots of important things still to study, and applied science and engineering can go on for ever. I hope we get a cure for cancer, and for mental disease, though there are few real signs of progress.

The term "the Big Bang" probably refers to（）

A. the genetic code theory

B. a geological theory

C. a theory of the origin of the universe

D. the origin and the power of atomic energy