？？Nazca was discovered in 1926 when______？？
A. the light shone on the lines
B. three explorers viewed the lines from above
C. the lines were not hidden by cjoud
D. the lines followed the rays of the sun
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某药物A的分解反应为一级反应，测得A在60℃分解的半衰期为0.21h，在30℃的半衰期为7.13h。计算此反应的活化能Ea和药物A保存在10℃时的半衰期。
请计算pH=7.20和pH=7.40的溶液中，氢离子浓度相差多少倍？
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A. moved on
B. ran away
C. fell down
D. raced off
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