杭州（30°N）某同学对传统的太阳能热水器进行改造：将支架改造成可活动的形式。请回答题。
小题1:为了充分利用太阳能，尽可能使一年内正午太阳光线与集热板保持垂直，集热板与地面夹角的调整幅度为
A．23° 26′
B．30°
C．46° 52′
D．60°小题2:一年中，活动支架最短的日期是
A．春分日
B．夏至日
C．秋分日
D．冬至日
小题1:C
小题2:B
题目分析：
小题1:正午太阳高度最大值出现在夏至日（直射北回归线），最小值在冬至日（直射南回归线）。为了充分利用太阳能，尽可能使一年内正午太阳光线与集热板保持垂直，集热板与地面夹角的调整幅度为46° 52′。
小题2:α角越大，支架越长；α角越小，支架越短。α角与正午太阳高度是互余的关系，要使支架一年中最短，正午太阳高度最大，杭州（30°N）最大正午太阳高度出现在夏至日。
点评：本题难度适中。以杭州（30°N）某同学对传统的太阳能热水器进行改造为材料，要求学生熟练掌握正午太阳高度的变化及应用。
Charles R. Drew was a medical student at Columbia University in New York. Before he graduated, he wrote an article __36___ blood bank, that is, the storing of blood. Up till then, a lot of people had died from loss of blood __37___ there was no blood bank. When the United States entered the Second World War, it became __38___ to set up blood banks. Dr Drew became _39___ of the Red Cross’s first blood bank. When the Red Cross __40___ blood banks to collect and store blood for men __41__ in battle, black American gave blood along with the whites. At ___42__ their blood was not accepted. Later blood from the blacks was ___43___ but was stored in a __44___ place from “white” blood. Although the best doctors __45___ that there was _46___ difference at all between the blood of blacks and whites, the Red Cross, with the support of the government, __47___ to separate black blood from white blood. After the war, Dr Drew was ___48__ from Washington with three other doctors to attend a medical meeting in a southern state. In northern Carolina their car went __49___ a ditch（深沟）and Dr Drew was _50___ hurt. He had lost __51__ blood by the time a passing car took him to the __52___ hospital. But they were stopped at the gate of the hospital. “__53__him to the hospital for blacks.” No matter __54___ they said, they could not get into the hospital. They had to take him to the __55___ hospital, but on the way Dr Drew died because he had lost too much blood.
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