根據(jù)短文內(nèi)容，從短文后的選項(xiàng)中選出能填入空白處的最佳選項(xiàng)。選項(xiàng)中有一項(xiàng)為多余選項(xiàng)。
A. Goods for auction (拍賣) sales
B. Definition of bidding
C. Way to sell more goods by auction
D. Auction sales in history
E. Brief introduction to auctions
F. Making a larger profit as an auctioneer
【小題1】______
Auctions 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 the goods. This is called “knocking down” the goods, for the bidding ends when the auctioneer strikes a small hammer on a table at which he stands.
【小題2】 ______
The ancient Roman probably invented sales by auction, and the English word comes from the Latin auction, meaning “increasing”. The Romans usually sold in this way the goods taken in war. In England in the eighteenth 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.
【小題3】 ______
Practically all goods whose qualities vary are sold by auction. Among these are coffee, skins, wool, tea, furs, silk and wines. Auction sales are also usual for land and property, furniture, pictures, rare books, old china and similar works of art.
【小題4】 ______
An auction is usually advertised beforehand with full particulars of the articles to be sold and where and when they can be viewed by potential buyers. If the advertisement cannot give full details, catalogues are printed, and each group of goods to be sold together, called a “l(fā)ot”, is usually given a number. The auctioneer need not begin with Lot 1 and continue in the order of numbers: he may wait until he notices the fact that certain buyers are in the room and then produce the lots they are likely to be interested in.
【小題5】 ______
The auctioneer’s services are paid for in the form of a percentage of the price the goods are sold for. The auctioneer therefore has a direct interest in pushing up the bidding as high as possible. He will not waste time by starting the bidding too low. He will also play on the opponents among his buyers and succeed in getting a high price by encouraging two business competitors to bid against each other.
=-1,這個(gè)數(shù)i叫做虛數(shù)單位。那么和我們所學(xué)的實(shí)數(shù)對(duì)應(yīng)起來(lái)就叫做復(fù)數(shù)，表示為
（a,b為實(shí)數(shù)），a叫這個(gè)復(fù)數(shù)的實(shí)部，b叫做這個(gè)復(fù)數(shù)的虛部，它的加，減，乘法運(yùn)算與整式的加，減，乘法運(yùn)算類似。
="_________," 
=____________
化簡(jiǎn)成
，即
，有下面的不等式：
當(dāng)且僅當(dāng)
時(shí)取到等號(hào)
叫做正數(shù)
叫做正數(shù)
，求函數(shù)
的最小值。
，則有
，得
，當(dāng)且僅當(dāng)
時(shí)，即
時(shí)，函數(shù)有最小值，最小值為
。
時(shí)，函數(shù)
取到最小值，最小值
的矩形花園，問這個(gè)矩形的長(zhǎng)、寬各為多少時(shí)，所
取何值時(shí)，函數(shù)
取到最大值，最大值為多少？
是一次函數(shù)，則m＝_______，且
隨
的增大而