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问题 填空题
已知点（x，y）在抛物线y2=4x上，则x2+
1
2
y2+3的最小值是______．
答案

x2+

1
2
y2+3=x2+2x+3=（x+1）2+2

∵x≥0∴x2+2x+3=（x+1）2+2的最小值为3，

此时x=0取到，

故答案为3．

单项选择题

Auctions (拍卖) are public sales of goods, conducted by an officially approved auctioneer. He asks the crowd assembled in the auction room to make offers, or "bids", for the various items on sale. He encourages buyers to bid higher figures, and finally names the highest bidder as the buyer of goods. This is called "knocking down the goods, for the bidding ends when the auctioneer bangs a small hammer on a table at which he stands, This is often set on a raised platform called a rostrum.

The ancient Romans probably invented sales by auction, and the English word comes from the Latin auction, meaning "increase". The Romans usually sold in this way the spoils taken in war; these sales were called "subusta", meaning "under the spear", a spear being stuck in the ground as a signal for a crowd to gather. In the eighteenth and nineteenth centuries goods were often sold by the candle’, a short candle was lit by the auctioneer; and bids could be made while it stayed alight.

The end of the bidding is called "knocking down" because ()

A. the auctioneer knocks the buyer down

B. the auctioneer knocks the rostrum down

C. the goods are knocked down on to the table

D. the auctioneer bangs the table with a hammer
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选择题

Every boy and every girl ________ pleased when they saw Shenzhou VI was sent up to space.

A．is

B．was

C．are

D．were
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