有哪些单词是由两个英语单词组成的

superstar,intercourse,hardship,friendship,relationship
还有词根词缀组成的，大部分的构词法是这样的

很多啊，superstar,intercourse,hardship,friendship,relationship

second-hand
classroom
background
bedroom

haircut 发型
firelight火光
hopeless 没希望的
太多了
一时想不起来

参考：
两个英语单词组成的词叫复合词,这样的词去了去了!
A．复合词的概念—
由两个或更多的词合成一个词的现象,叫复合词,又称合成词（词与词之间可以有连字符）；其中以复合名词最多,其次是复合形容词,复合动词、介词、副词、数词等也不少.
B．复合名词
a．名词＋名词：bookshop ／store ／seller ／ mark,sunlight ／shine ／glasses,French ／Englishman,policeman ／woman,volley ／basket ／base ／ football,penfriend,grandfather ／mother ／son ／ daughter ／parent（s）／children,schoolboy ／girl／ bag ／yard,headache ／master ／teacher,moon- cake ／light,team ／house ／homework,workbook ／place ／shop,newspaper,motorbike ／car,birthday,bed ／class ／bathroom,handbag,gate- keeper ／man,pencil-box,day ／lunchtime,lifeboat ／time,postcard ／man ／office,seafood,weekday ／end,class ／work ／mate,northeast ／ west,railway,southeast ／west,textbook,teapot,shellfish,earthquake,cup ／keyboard,doorbell,fireplace,farmland,hometown,salesgirl,necklace,wardrobe,spaceship,etc．
b．形容词＋名词：loudspeaker,goodbye,midnight ／day,blackboard,Mid-autumn,software,mainland．．．
c．动名词＋名词：sitting ／waiting-room．．．
d．动词＋名词：playground ／house,watchtower,chopsticks,washroom,checkout,breakfast．．．
e．名词＋动名词：handwriting,homecooking,thanksgiving,roller-skating．．．
f．动词＋副词：get-together
g．其它：afternoon,today,tonight（n．＆ adv．）,ping-pong,T-shirt,E-mail,
self-respect,two-storey,yo-yo．．．
C．复合形容词
a．形容词＋名词＋（e）d：kind-hearted,glass－topped
b．形容词＋现在分词：good-looking
c．副词＋现在分词：hard-working
d．名词＋现在分词：English-speaking
e．名词＋过去分词：man-made
f．副词＋过去分词：well-known
g．形容词＋名词：mideast,round-trip
h．其它：up ／downstairs（adj．＆adv．）,everyday,take-away,outdoor,one-way,part- time ,two-month ／day ／year ／metre（-old ／long etc．）secondhand,mouth-to-mouth,so-so,on- line,so-called．．．
D．其它复合词
maybe,forever,everything ／body ／one／ where,nothing ／body ／where,something ／ body ／one ／where,anything ／body ／one／ where,myself,ourselves,when ／how／who／ what ／whichever,wherever,without,into,in／ outside,sometime（s）,thirty-eight,forty-fifth,water-ski,download,half-way,nearby,etc．
II．缩写词
A．缩写词概念B．长单词变短单词网页C．一个首字母即代表一个单词网页
A．缩写词概念—
由一个长单词或二个以上的单词缩为一个短单词（更可简到只剩廖廖几个骨架字母）,叫缩写词又名缩略词.
B．长单词变短单词—
a．截头：telephone—phone,bicycle—cycle,aeroplane—plane,etc．
b．去尾：mathematics—math（s）,photo- graph—photo,Monday—M on．,October—Oct．,adverb—adv．（ad．）,kilogram—kilo,examina- tion—exam ,advertisement—ad．,laboratory— lab,etc．
c．既截头又去尾：refrigerator—fridge
d．混合词（各取两词的一部分刷新成另一词）：breakfast and lunch—brunch
e．其它：cannot—can't,will not—won't,shall not—shan't,let us—let's,I would（had）— I'd,she is（has）—she's,you are—you're,number—No．（or num．）,Catherine—Kate,I will（shall）—I'll,bicycle—bike,mister—Mr．,etc．
C．一个首字母即代表一个单词网页（注：多数要大写,组合成像单词一样的常见缩写词）.如：very important person—VIP,physical education—P．E等
CD,BBC,CAAC,ID,IQ,IT,UFO,SAR,OK,CBA,MBA,WTO,UNESCO,PLA,PRC,AD,CCTV,CCP,EM S,USA,p．m．,kg,km,cm,mm,a．m．,etc．（注：它们一般按字母读音读,如PC／'pi:'si／；但像UN- ESCO ／ju（:）'neskou ／等也可当作一个单词来拼读）.

很多
复合词,如书包－bookbag,铅笔盒－pencil box绿茶－red tea，

应该这样说，绝大多数的英语单词都是由词根+扩展构成的。如果词根和扩展都可以单独成词，那你可以说他是由两个英语单词构成的。