2.以－o结尾的名词，变复数

　(1)加s，如：photo-photos　piano-pianos　radio-radios　zoo-zoos　kilo-kilos

　(2)加es，如：potato-potatoes　tomato-tomatoes　Negro-Negroes　hero-heroes

　歌诀记忆：黑人(Negro)和英雄(hero)爱吃西红柿(tomato)和马铃薯(potato)。除了这四个以－o结尾的名词加－es外，其余的以－o结尾的名词加－s。

1.以－f或－fe结尾的名词变复数

　(1)加－s，如：

　belief-beliefs　roof-roofs　gulf-gulfs

　(2)去f，fe加－ves，如：

　half-halves　knife-knives　leaf-leaves　life-lives　wolf-wolves

　thief-thieves　self-selves　wife-wives　shelf-shelves

歌诀记忆：树叶(leaf)半数(half)自己(self)黄；妻子(wife)拿刀(knife)去割粮；架(shelf)后窜出一匹狼(wolf)；就像小偷(thief)逃命(life)亡。这9个名词变复数时，都要改－f(e)为v，再加－es，其他的以－f(e)结尾的名词则直接加－s变复数。

6.有过去式，没有过去分词的动词

　can-could　may-might　must-must　shall-should　will-would

　不规则名词复数形式

5.A-B-C型(现在式、过去式和过去分词都不相同)

　(1)in、im的变化(i-a-u型)

　sing-sang-sung　ring-rang-rung　begin-began-begun

　drink-drank-drunk　swim-swam-swum　sink-sank-sunk

　(2)在动词原形后加－n或－en构成过去分词

　①ow及aw的变化(过去式以ew结尾，过去分词以wn结尾)

　draw-drew-drawn　know-knew-known　throw-threw-thrown

　blow-blew-blown　grow-grew-grown　fly-flew-flown

　②元音是i的开音节的变化(过去分词以en结尾)

　drive-drove-driven　rise-rose-risen　ride-rode-ridden

　write-wrote-written　give-gave-given

　③其他

　see-saw-seen　eat-ate-eaten　take-took-taken　fall-fell-fallen　freeze-froze-frozen　show-showed-shown　break-broke-broken

　speak-spoke-spoken　wake-woke-woken　choose-chose-chosen

　forget-forgot-forgotten　lie(躺，放)-lay-lain　wear-wore-worn

　be(am，is，are)-was/were-been

　(3)其他

　go-went-gone　do-did-done

4.A-B-B型(动词的过去式与过去分词相同)

　(1)词尾的“d”变为“t”或词尾是“n”加“t”

　build-built-built　lend-lent-lent　send-sent-sent　spend-spent-spent

　burn-burnt/burned-burnt/burned　learn-learnt/learned-learnt/learned

　mean-meant-meant

　(2)把原形变为aught及ought的变化(如果原形有a则是aught，无a则是ought)

　buy-bought-bought　bring-brought-brought　think-thought-thought

　fight-fought-fought　catch-caught-caught　teach-taught-taught

　(3)eep变ept或过去式、过去分词含有/e/音的动词

　keep-kept-kept　sleep-slept-slept　sweep-swept-swept　leave-left-left

　say-said-said　meet-met-met　spell-spelt-spelt

　smell-smelt/smelled-smelt/smelled　hold-held-held　feel-felt-felt

　(4)其他

　dig-dug-dug　find-found-found　stand-stood-stood

　understand-understood-understood　get-got-got　sit-sat-sat

　spoil-spoilt-spoilt　have/has-had-had　sell-sold-sold　tell-told-told　hang-hanged/hung-hanged/hung　hear-heard-heard　make-made-made

　pay-paid-paid　lay-laid-laid　lie(说谎)-lied-lied　lose-lost-lost

　shine-shone/shined-shone/shined　win-won-won　shoot-shot-shot

3.A-B-A型(现在式和过去分词同形)

　come-came-come

　become-became-become

　run-ran-run

2.A-A-B型(现在式和过去式同形)

　beat-beat-beaten

1.A-A-A型(无变化的动词)

　cut-cut-cut　let-let-let　hit-hit-hit　put-put-put　cost-cost-cost　hurt-hurt-hurt　read/ri?d/-read[red]-read[red]

25. People believe that computer skills will enhance their job opportunities or promotion opportunities.

　　 人们相信拥有计算机技术可以获得更多工作或提升的机会。

24. We should spare no effort to beautify our environment.

　　 我们应该不遗余力地美化我们的环境。