【时态讲解】一般现在时

一、 定义与讲解

      一般现在时：表示经常性，习惯性的动作或状态。

时间状语：often 经常，usually通常，always 总是，every每个，sometimes 有时，never从不，seldom 极少

结构：

❶主语＋am/is/are＋表语……

❷主语＋动词原形 （第三人称单数Vs/es）……

第三人称单数变化：

(1)直接在动词词尾加-s.

如：ask---asks    work---works

      get---gets      stay---stays

(2)以字母s, x, ch, sh或o结尾的动词，在词尾直接加-es.

如：watch---watches    wish---wishes

      fix---fixes              do---does

      go---goes            pass---passes

(3)以“辅音字母加 - y”结尾的动词，要先变y为i再加-es.

如：try---tries      study---studies

      cry---cries    fly---flies

2.不规则变化：

be---- is are have----has

二、一般现在时用法

1. 表示经常性，习惯性,永久性的动作或存在的状态.通常与副词sometimes, often, usually, always, every day (year, month ), once (twice, three times) a day,等时间状语连用。

They usually go to school by bike.

I take the medicine three times a day.

She helps her mother once a week.

Mary’s father is a policeman.

There are 50 students in my class.

2. 表示客观真理，科学原理，自然现象，等客观事实或格言，谚语等。

The sun rises in the east and sets in the west every day.

Tomorrow is Tuesday.

三、一般现在时的句子转换：

(1)当句子中有be动词或情态动词时，则把be动词或情态动词(can,could等等)提到主语的前面变成疑问句;在be动词或情态动词后面加not变成否定句.

例：①陈述句：She is a student.

疑问句→ Is she a student?

否定句→ She is not a student.

②陈述句：I can swim.

疑问句→ Can you swim

否定句→ I can not swim.

(2) 当句子中即没有be动词，也没有情态动词时，则在主语前加助动词do (you,以及复数), does(单数she,he,it)变成问句;在主语后谓语动词前加助动词don’t(I,you,以及复数), doesn’t(单数she,he,it)变成否定句，助动词后的动词要变成动词原形。

例：①陈述句：We get up at 7:00 every morning.

疑问句→Do you get up at 7:00 every morning?

否定句→We don’t get up at 7:00 every morning.

②陈述句：She has a little brother.

疑问句→ Does she have a little brother?

否定句→ She doesn’t have a little brother.