牛津英语5a英语语法(三)一般现在时
一. 一般现在时行为动词词型变化形式
一般现在时动词只有第三人称有词形变化，其他人称动词均用原形单数第三人称动词变化：
多数在动词后加s play—plays like—likes ,
以s，x，sh，ch，o结尾的动词加es go—goes wash--washes,
以辅音字母加y结尾，把y改i再加es fly—flies study--studies
二. 一般现在时动词be和 have的变化形式
1.动词be 叫连系动词, 连系动词be的用法：除了第一人称单数用am，和第三人称单数用is以外，其它人称用are。
i am busy. you are busy. he (she) is busy. we (you, they) are busy.
2.动词have的用法：除了第三人称单数用has以外，其它人称一律用have。如:
i have a pen. you have a pen. she (he) has a pen.
we (you, they) have pens.
三. 一般现在时的句型
1.肯定句构成：主语+动词 (注意人称变化) +其它成分
ihave a dog. we like the little cat. she sings well.
2.否定句构成：
行为动词的否定句：主语+助动词(do/does) + not +动词原形+其它成分
he dosen’t have a dog. he isn’t young. we don’t like the little cat.
(借助于助动词do) she doesn’t sing well. (借助于助动词does)
3.一般疑问句：
a.行为动词的一般疑问句：助动词(do/does)+主语+动词原形 + 其它成分
do you like it? yes, i do. / no. i don’t . does he(she) like it? yes, he( she )does. / no, he ( she )doesn’t.
b. 动词be 的一般疑问句am / is /are +主语 + 其它成分
are you a teacher? yes, i am. / no, i am not.
are they students of your school.yes they are / no they aren,t.
4.特殊疑问句：特殊疑问词 + 一般疑问句
how many students are there in your school?
what do you usually do on sunday?
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。如：
every year, sometimes, at 5 o’clock, on sunday.
i get up at six o’clock every day.
he gets up at six o’clock every day.
she smokes too much.
i telephone to my parents once a week.
2.表达客观真理，科学事实。如果出现在宾语从句中，即使主句是过去时，从句谓语也要用一般现在时。
three and four makes seven.
the teacher told us that the earth moves around the sun.
shenyang lies in the north of china.
3.在格言或名言警句中。
pride goes before a fall. 骄必败。
actions speak louder than words.事实用于雄辩。
4.表示现在的状态、性格、个性。
i don’t want more, thanks.
he is a good student. he is always ready to help others.
五.一般现在时其它用法
一般现在时表将来
1.含有go, come, return, arrive, leave, start, begin等动词的一般现在时表将来。表示在时间上已确定或安排好的事情。
the school bus leaves at eight .
2.在时间或条件句中。
when tom comes, ask him how to fix the tap.
i’ll help you as soon as i arrive there.
3.在动词hope, take care that, make sure that等后。