【正文】 per t dri ver s, but bef ore they dri ve any of t he buse s, t hey wil l have t o pass a speci al t est . The st udents ar e goi ng to take the t est i n two days39。s house. When he asked i f Lane l ived ther e, t he pol iceman on duty t old hi m t ha t si nce hi s def eat , t he exPr ime Mini st er had gone abroad. On the f oll owi ng day, Cr awley went t o the house again. The same policema n was j ust walki ng slowly past the entr ance, when Crawl ey asked the same quest ion. Though a lit tl e suspici ous t his t ime, the pol i cem an gave him the same answer . The day af ter , Cr awl ey went t o the house once m or e and asked exact ly t he same questi on. This t im e, t he pol iceman l ost his t em per .39。s Radi cal Progr essive Part y. Af t er t he elect ions, Crawl ey went t o the f orm er Pr im e Mi nister39。f r e r i des39。 asked the i nspector. 39。 39。 lesson90 f or supper ？ 晚餐吃什么？ Though Br azi l is one of the r ichest count ri es in t he worl d, much of i t has not yet been devel oped. It was mai nl y f or t his r eason that the Br azil an gover nment decided to have a new ci ty bui lt 600 mi les nort h west of Ri o de Janeir o. Desi gned by t he great ar chitect Cost a, t he new cit y, Br asi li a, r eplaced Ri o de Janei ro as t he capi tal of i n 1960. Br asi li a has been careful ly pl anned f or moder n li ving. It s wide r oads, which can t ake f ourt en l anes of tr af ic, have been kept away f rom li ving areas. Chi ldr en do not have to cr oss busy st r eet s to go t o school . Housewives can vi sit shoppi ng on foot, f or in t hese speci al ly designed li ving areas, cars ar e unnecesary. At f ir st , t he gover nment had gr eat dif fi cul ty i n pers uadi ng peopl e to l eave Ri o and t o set tl e in Br asi li a. Si nce 1960, however, t he popul at ion has been gr owing al l the ti me. Bras il ia has quickly establi shed i tself as the capital of the countr y. The i dea t o have the capital moved so far i nl and wil l have a gr e at ef fect on the f ut ure of Br azi l. Leson91 Three men i n a basket 三人同籃 A pil ot not iced a bal loon whi ch seemed t o be making f or a Royal Ai r Force Stat ion nearby. He inf ormed t he stati on at once, but no one there was abl e to explai n the m yst er y. The of fi cer i n t he contr ol tower was ver y angry when he heard the news, because baloons can be a great danger to ai rcraf t. He said t hat someone might by spyi ng on the st at ion and t he pi lot was order ed to keep tr ack of t he st range object. The pil ot m anaged to ci rcl e the bal oon for som e ti me. He coul d make out thr e men in a basket under i t and one of t hem was holding fi el dglasses. When t he bal loon was over t he st ati on, t he pi lot saw one of the m en t aki ng phot ogr aphs. Soon aft er wards, the bal oon began to descend and i t landed near an ai rf iel d. The poli ce were cal ed in, but they coul d not ar rest anyone, f or the basket cont ai ned two Members of Parl iament and the Comm anding Of f icer of t he stati on! As the Comm anding Of icer expl ai ned later , one half of t he st at ion di d not know what t he other hal f was! Leson92 Aski ng for t rouble 自找麻 煩 It m ust have been about t wo i n the m or ning when I r eturned home. I tr ied t o wake up my wif e by r inging t he door bel , but she was fast asleep, so I got a l adder fr om t he shed i n the gar den, put i t agai nst the wal l, and began cli mbi ng towards t he bedr oom wi ndow. I was alm ost t her e when a sar cast ic voice below sai d, 39。s busy wor king, but woul d you mind i ng wi th me to t he Wel l , I 39。倒立擺系統(tǒng)存在嚴(yán)重的不確定性，一方面是系統(tǒng)的參數(shù)的不確定性，一方面是系統(tǒng)的受到不確定因素的干擾。在倒立擺系統(tǒng)中含有極其豐富和 復(fù)雜的動力學(xué)行為，如分叉、分形和混沌動力學(xué)，這方面的問題也值得去探討和研究。 he shout ed, Lane was def eat ed in the electi ons. He has reti r ed f r om poli ti cal li f e and gone t o li ve 39。s hom e. We shal al l r emember Page f or hi s patience and under st andi ng and f or the ki ndl y encouragement he gave us when we went so unwil li ngl y to school. A gr eat m any f orm er pupil s wi l be atending a farewel l di nner i n his next Thur sday. It i s a cur ious coincidence t hat t he day bef ore hi s reti rement , Page wi l have been t eaching f or a total of for ty years. Af ter he has r eti red, he wil l devote hi msel f to gar deni ng. For him, t his wi l be an enti rely new hobby. But this does not m at ter , for, as he has oft en remarked, one i s never t oo ol d t o learn. Leson86 Out of contr ol 失控 As the m an tr ied t o swi ng t he speed boat r ound, the st er ingwheel came away i n hi s hands. He waved desper ately t o his panion, who had been wat er ski ing f or t he last fi ft en m inutes. Bot h m en had hardl y had ti me t o reali ze what was happeni ng when the y wer e thr own violent1y into the sea. The speedboat had st ruck a buoy, but it continued t o move very quickl y acr oss t he water. Bot h men had j ust begun t o swim t owar ds the s hore. they noti ced wi th dismay that the speed boat was moving i n a ci rcle. It now came st raight towar ds them at tr emendous speed. In les than a mi nut e, i t roared past them only a few feet away. Af ter it had pased, t hey swam on as qui ckly as t hey could because t hey knew t hat t he boat would soon r eturn. They had just had enough ti me t o swi m out of danger when t he boat agai n pleted a ci rcle. On t his occasion, however , i t had sl owed down consider abl y. Bef or e l ong, the noi se dr opped plet el y and the boat began to dri ft gent ly acr oss t he water. Leson87 A per fect al ibi 極好的不在犯罪現(xiàn)場的證據(jù) 39。 I m ust be at work at o39。 said the i nspect or, 39。 I l ooked down and near ly fel of f the ladder when I saw a pol iceman. I imm edi at ely r egr et ed answeri ng in the way I did, but I sai d, 39。You see, I 39。研究者常常是希望通過對倒立擺控制系統(tǒng)的研究獲得性能較為突出的新型控制器設(shè)計方法，并驗證其有效性及控制性能。 倒立擺系統(tǒng)的分類 倒立擺系統(tǒng)誕生之初為單級直線形式，即僅有的一級擺桿一端自 由，另一端鉸接于可以在直線導(dǎo)軌上自由滑動