be是一個(gè)連系動(dòng)詞,它有自己不同的形式
現(xiàn)在時(shí)：be 進(jìn)行時(shí)：being 過(guò)去時(shí)：was/were 過(guò)去分詞：been
它的后面必須跟形容詞或名詞作表語(yǔ),與之構(gòu)成系表結(jié)構(gòu),充當(dāng)句子的謂語(yǔ).
i am a student主語(yǔ)：i 謂語(yǔ)：am a student（系表結(jié)構(gòu)）
being是它的現(xiàn)在進(jìn)行時(shí)態(tài),一般不單獨(dú)用,而是用于現(xiàn)在進(jìn)行時(shí)的被動(dòng)語(yǔ)態(tài).（being+動(dòng)詞過(guò)去分詞）
the bike is being repaired.單車正在被修理中.
it is being finished by him這正在被他完成中.
been是它的過(guò)去分詞,也不一般單獨(dú)使用,而是用于現(xiàn)在完成時(shí)、過(guò)去完成時(shí)以及需要它的句子.
i have been here for a long time.我已經(jīng)到這里有一段時(shí)間了.
至于你的問(wèn)題,這與你想表達(dá)的意思有關(guān).
你的工作是什么?
what do you do?what is your job?
那么這里選用do和is有什么根據(jù)呢?
第一句里面,第二個(gè)do是指你做什么,也就是你的工作,就是一個(gè)實(shí)義動(dòng)詞.按中文說(shuō),what you do已經(jīng)足夠了.可是英語(yǔ)里面就不行,必須跟一個(gè)助動(dòng)詞,也就是do.
這里就有了一個(gè)結(jié)論：當(dāng)句子中有動(dòng)詞時(shí),我們就用助動(dòng)詞do或是does.如果沒(méi)有動(dòng)詞時(shí),我們就選用is或是are,也就是b“Be”除了原形的“be”之外,還有另外七種形式：am,is,are,been,being,was,were.
在句子中,“be”可以是主動(dòng)詞(The Principal Verb)或助動(dòng)詞(The Auxiliary Verb).
當(dāng)主動(dòng)詞時(shí),“be”在性質(zhì)上屬于接系動(dòng)詞(The Linking Verb),后面要有名詞、形容詞、地方副詞或短語(yǔ)作補(bǔ)足語(yǔ)(The Complement).例如：
1.The man is a science teacher.
2.Mary's new dresses are colourful.
3.I have been there before.
4.Mother is in the kitchen now.
這四個(gè)都是陳述句,可以變成疑問(wèn)句,方法簡(jiǎn)單,把主語(yǔ)和“be”或助動(dòng)詞對(duì)換位置即可：
5.Is the man a science teacher?
6.Are Mary's new dresses colourful?
7.Have I been there before?
8.Is mother in the kitchen now?
當(dāng)“be”要在祈使句中出現(xiàn)時(shí),它必須借重助動(dòng)詞“do”或“don't”之助,如：
9.Don't be silly!
10.Do be obedient!
11.Don't be a fool!
“Be”有兩種縮寫(xiě)法,如下：
12.He's not./He isn't.
13.You're not./You aren't...
但“am + not”的縮寫(xiě)法只有一個(gè)：
14.I'm not.
有人用“ain't”,但這并不是標(biāo)準(zhǔn)英語(yǔ).
談過(guò)了“be”作主動(dòng)詞的功能,現(xiàn)在看看“be”作助動(dòng)詞時(shí),有些什么用法：
1.“Be + 現(xiàn)在分詞”以組成進(jìn)行式時(shí)態(tài)(Continuous Tenses),如：
15.Tony's maid is washing his new car.
16.The children are playing in the field.
17.Samuel was eating when I came in.
18.We have been living here since 1959.
2.“Be + 過(guò)去分詞”以組成被動(dòng)語(yǔ)態(tài)(The Passive Voice),如：
19.Her money in the drawer was stolen.
20.A number of good jobs are taken up byforeigners.
21.David studied in Taiwan but has been trained as a language lecturer in America.
22.Can all the wonderful birds be found in our Bird Park?
23.The disobedient boy was told to stand out- side the classroom.
24.Steps are being taken to reduce traffic con- gestion during peak hours.
25.Dishonest students will be immediately dealt with.