有以下几种情况：
1.在专有名词和不可数名词前.
I’m going to England next week for a holiday.下周我将要去英国度假.
2.可数名词前已有作定语的物主代词my,your,his,her等；指示代词this/ these,that/those; 不定代词some,any等及所有格限制时.
The letter is in her pocket.信在她的衣袋里.
3.复数名词表示一类人或事物时.
My father and mother are teachers.我的父亲和母亲是教师.
4.在星期、月份、季节、节日前.
The best time to come to China is in spring or autumn.到中国来的最好时间是春季或秋季.
Today is Thursday,September 10th,Teacher’s Day.今天是九月十日,星期四,教师节.
[注意] 如果月份、季节等被一个限定性定语修饰,则要加定冠词.
He joined the Army in the spring of 1982.他在1982年春季参军.
5.在称呼语或表示头衔的名词前.
Happy Teachers’ Day,Miss Zhao!
Here it is,Mom!
6.在学科名称、三餐饭和球类运动名称前.
I think Chinese is more popular than any other subject.我认为汉语比其它学科更普及.
Can you play basketball?你会打篮球吗?We are going to play football.我们去踢足球.
[注意]I can see a football.(指足球,并非“球类运动”)
Where’s the football.
7.某些固定词组中不用冠词.
①与by连用的交通工具名称前
by bus,by car,by bike,by train,by air/plane,by sea/ship
②名词词组
day and night,brother and sister,hour after hour,here and there
③介词词组
at home在家in surprise惊奇地
at noon在中午on foot步行
at night在晚上on duty值日
at work在工作on time准时
for example例如on business经商
in school在上学on holiday在度假
in class在上课on show展览
in hospital在住院on top of在……顶部
in bed在床上
④ go短语
go home回家go to bed上床睡觉
go to school去上学go to work去上班
go shopping/swimming/boating/fishing去买东西/游泳/划船/钓鱼
