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问题 单项选择题

最常用于早孕诊断的激素是（）

A.雌酮

B.雌二醇

C.雌三醇

D.孕酮

E.人绒毛膜促性腺激素

答案

参考答案：E

解析：人绒毛膜促性腺激素可用于早早孕检测，最早在受精后7天即可检测出受孕。

填空题

已知CaCO3+H2O+CO2===Ca(HCO3)2，Ca(HCO3)2易溶于水。某实验小组在含一定量Ca(OH)2的石灰水中通入CO2，产生沉淀的量与通入CO2气体的量的关系如图所示，回答下列问题：

(1)写出石灰水中刚通入CO2时的化学方程式                      。

(2) 至少通入             gCO2气体，溶液的质量是整个实验过程中溶液质量的最大值（不考虑CO2气体在水中的溶解性）。

(3) 请描述整个实验过程的现象                        。
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单项选择题

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 p, 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 p 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．damage

B．hurt

C．injury

D．profit
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