一般现在时结构
1、主系表(名词、形容词、介词短语)
be动词的一般现在时有三种形式，即：am， is， are。
肯定句
I am a middle school student. 表身份（表语为名词）
I am really tired. 表状态（表语为形容词）
I am from Korea. 表处所 （表语为介词短语）
否定句：系动词后加 not
一般疑问句：系动词置于主语前，句号变问号。
缩写: we are=we're they are=they're
you are=you're aren't=are not
he is=he's my mother is=my mother's
isn't=is not that's=that is
注意：This is不可缩写。am not不缩写。
2、主谓宾
肯定句式: 主语+动词原形/动词的第三人称单数+其他
I want to see you.
Bill often goes to school at 7:00 in the morning .
否定句式: 主语+（助动词）don't/doesn't +动词原形+其他
I don't want to see you.
Bill doesn't often go to school at 7:00 in the morning.
一般疑问句式: Do/Does+主语+动词原形+其他?
简略回答: (肯)Yes， 主语+do/does (否)No， 主语+ don't/ doesn't
缩写形式: don't=do not doesn't=does not
Do you want to see me? Yes， I do. /No， I don't
--Does Bill often go to school at 7:00 in the morning?
--Yes， he does. /No， he doesn't.
四、一般现在时的用法
1、经常性或习惯性的动作，常与表示频度的时间状语连用。
表示频率的副词：always， often， usually， sometimes…
时间状语：on Sundays， every day， every morning， every year…
表示频率的词组：once a year， three times a week…
I leave home for school at 7 every morning.
2、表示客观真理，客观存在，科学事实。
The earth goes around the sun. 地球绕着太阳转。
3、表示格言或警句中。
Practice makes perfect. 熟能生巧。
4、现在时刻的状态、能力、性格、个性。
Miss Wang writes good English but does not speak well.
5、在某些以 here， there开头的句子中，一般现在时表示正在发生的动作。
Here comes a bus .公交车来了
6、在时间状语从句、条件状语从句中，如果主句是一般将来时，从句用一般现在时替代一般将来时。常见标志词有 if， when， as soon as， before， after， while等。
I will tell him about it when he comes.
If it is fine tomorrow， we will go outing.
