【正文】 up the tal CN Tower and l ooked acros the l ake. In the di stance, they coul d see the Mi sty cl oud that rose from the great N i agara Fal s, whi ch is on the south si de of the l ake. The water fl ows into the N iagara Ri ver and over the fal ls on its way to the sea. They saw the covered stadi um , hom e of several fam ous basketbal team s. As they wal ked north from the harbour area, Li Dai yu sai d, “Li n Fang, one of m y mother’s ol d school mates, lives here. I should phone her from a tel ephone booth. ” They met Lin Fei around dusk i n downtown Chinatown, one of the three i n Toronto. O ver dinner at a restaurant cal ed The Pink Pearl, the cousins chatted wi th Lin Fei, who had moved to Canada m any years earli er. “We can get good Cantonese food here,” Li n Feitold them, “ because most of the Chi nese peopl e here e from South Chi na, especial y H ong Kong. It’s too bad you can’t go as far as Ottawa, Canada’s capi tal . It’s approxi matel y four hundred kil ometers northeast of Toronto, so it woul d take too l ong. ” The train left late that ni ght and arrived i n Montreal 1第一部分：我們的使命 第一章 健康、疾病與藥品 在日常生活中，當(dāng)身體出現(xiàn)發(fā)燒、頭痛等癥狀時(shí)，說(shuō)明我們生病了，身體不再健康。a chance to make a tri p i nto space wi th m y friend Li Yanpi ng, an astronom er. We vi si ted the m oon i n our spaceshi p! Before we l eave, Li Yanping expl ai ned to m e that the forece of the gravi ty woul d change three ti m es on our journey and that the fi rst change woul d be the m ost powerful . Then we were off. As the rocket rose i nto the ai r, we were pushed back i nto our seats because we were tryi ng to escape the pul of the earth’s gravi ty. It was so hard that we coul d not say anythi ng to each other. Gradual y the wei ght l essened and I was abl e to tal k to hi m. “ Why i s the spaceshi p not fal i ng back to the earth? O n the earth i f I fal l from a tree I wil l fal l to ground. ” I asked. “ We are too far from the earth now to feel i ts pul, “ he expl ai ned, “ so we feel as i f there is no gravi ty at al. When we get cl oser to the m oon, we shal feel its gravity pul i ng us, but i t wi l not be as strong a pul l as the earth’s. “ I cheered up imm edi atel y and fl oated wei ghtl esl y around i n our spaceshi p cabi n watchi ng the earth be e sm al l er and the m oon l arger. When we got there, I wanted to expl ore i mm edi atel y. “ Com e on, ” I sai d. “ If you are ri ght, m y m as wi l be l ess than on the earth because the m oon is sm al l er and I wi l be abl e to m ove m ore freel y. I mi ght even grow tal er i f I stay here l ong enough. I shal certai nl y weigh l ess!” I l aughed and cli mbed down the steps from the spaceshi p. But when I tri ed to step forward, I found I was carri ed twi ce as far as on the earth and fel l over. “ O h dear, ” I cri ed, “ wal ki ng does need a bi t of practi ce now that gravi ty has changed. ” After a whil e I got the hang of i t and we began to enjoy oursel ves. Leavi ng the m oon’s gravi ty was not as pai nful as l eavi ng the earth’s. But returni ng to the earth was very fri ghteni ng. We watched, amazed as fi re broke out on the outsi de of the spaceship as the earth’s gravi ty increased. Agai n we were pushed back hard i nto our seats as we cam e back to l and. “ That was very exhausti ng but very exciti ng too, ” I sai d. “N ow I know m uch m ore about gravi ty! Do you thi nk we coul d bisi t som e stars next tim e?” “O f course,” he sm il ed, “ whi ch star woul d you l i ke to go to?” Caught by a bl ack hol e The spaceship warned Li Yanpi ng and m e to be ready as we were approachi ng the “black hol e”. We coul d see som e fai nt l i ghts around what l ooked li ke an em pty space. Li Yanpi ng sai d, “ That em pty hol e i s l i ke a m outh al ways needi ng to be fed. Those l i ghts are thi ns that are being pul ed i nto tim e by the gravity of the hol e.” We watched with i nterest and am azem ent at the li ghts whi ch seem ed to be goi ng fai nter and fai nter round the edge of the bl ack hol e. Just then the li ghts on our spaceshi p went our the and the puter stopped working. What was happeni ng? I tri ed to turn the spaceshi p away from the hol e but i t woul d not m ove. Woul d i t eat us too? Suddenl y the spaceshi p jum ped and began to m ove round the edge of trhe hol e too. The gravi ty of the “black hol e” was pul li ng us i nto i ts “m outh”. As the spaceshi p m oved round the bl ack hol e, I fel t rather si ck. My m outh went dry and I cl osed m y eyes. Al l the stori es about what happened when you were caught by the gravi ty of a “bl ack hol e” seem to be true. But then the spaceship jum ped agai n. Thi s tim e i t m oved si deways and away from thi s edge of the “bl ack hol e”. Som eone watchi ng m e woul d have seen the spaceshi p flyi ng li ke a bi rd away from the “bl ack hol e”. But we fel t nothi ng. At l ast we were abl e to l ook around us. Luckil y the puter had started worki ng agai n. We real i zed that we had di scovered som ethi ng new about “black hol e”. If you go i nsi de the edge of a “black hol e”, i t wil l “eat” you and there i s no escape。 but i f you do not, you m ay have an opportuni ty to escape. H ow exciti ng! Unit 5 A tri p on “ The True North” Li Dai yu and her cousin Li u Qian were on a tri p to Canada to bi si t their cousi ns i n Montreal on the Atl anti c coast. Rather than take the aeropl ane al the way, they deci ded to fl y to Vancouver and then take the trai n west to east acros Canada. The though that they coul d cross the whol e continent was exci ti ng. Thei r fri end, Danny Li n, was waiti ng at the ai rport. H e was goi ng to take them and thei r baggage to catch “The True N orth”, the cross Canada train. O n the way to the stati on, he chated about thei r tri p. “You ’re goi ng to see som e great scenery. Goi ng eastward, you’l l pass m ountai ns and thousands of l akes and forests, as wel as wi de ri vers and large ci