单项选择题

In the figure at the right, the legs of fight triangle ACB are diameters of the two semicircles. If AB = 4, what is the sum of the areas of the semicircles（）

A. π
B. 2π
C. 4π
D. 8π
E. 16π

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单项选择题

If a is increased by 25% and b is decreased by 25%, the resulting numbers will be equal. What is the ratio of a to b（）

A.A
B.B
C.C
D.D
E.E

单项选择题

Making snow angels usually falls under the category of children’s winter recreation, but in early 2007, the process took on a whole new meaning. Almost 9,000 people gathered on the state Capitol grounds in Bismarck, North Dakota, to set a new world’s record for the most people making snow angels at one time. They were determined to break Michigan’s record of 3,784. Participants ranged from families with children to snowplow drivers. One woman was there to mark her 99th birthday! Kids of all ages flapped their arms in the snow and a young baby even made a snow angel by having her car seat spun in circles. In the context in which it appears, mark most nearly means （）

A. memorialize
B. remember
C. identify
D. define
E. celebrate

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