ty将y变成i，th前面有个e.

若是碰到几十几，前用基来后用序。

六、介词：常用介词：in, on, at, behind等

1.at表示时间概念的某一个点。(在某时刻、时间、阶段等)。

??at 1：00(dawn，midnight，noon)在一点钟(黎明、午夜、中午) ??

2.on

1)表示具体日期。

注：(1)关于"在周末"的几种表示法：

??at(on)the weekend?在周末---特指

??at(on)weekends?在周末---泛指

??over the weekend?在整个周末

??during the weekend?在周末期间

? (2)在圣诞节，应说at Christmas?而不说on Christmas?

2)在(刚……)的时候。

On reaching the city he called up his parents.

一到城里他就给父母打了一个电话。

3.in

1)表示"时段"、"时期"，在多数情况下可以和during互换，前者强调对比，后者强调持续。 in(during)1988(December，

the 20th century)在一九八八年(十二月、二十世纪)

七、动词：动词的四种时态：

(1)一般现在时：

一般现在时的构成

1. be动词：主语+be(am, is, are)+其它。如：　I am a boy. 我是一个男孩。

2. 行为动词：主语+行为动词(+其它)。 如： We study English. 我们学习英语。

当主语为第三人称单数(he, she, it)时，要在动词后加"-s"或"-es"。如：Mary likes Chinese.玛丽喜欢汉语。

动词+s的变化规则

1.一般情况下，直接加-s，如：cook-cooks, milk-milks

2.以s. x. sh. ch. o结尾，加-es，如：guess-guesses, wash-washes, watch-watches, go-goes

3.以“辅音字母+y”结尾，变y为i, 再加-es，如：study-studies

(2)一般过去时:

动词过去式详解 动词的过去式的构成规则有：

A、规则动词

① 一般直接在动词的后面加ed：如　worked , learned , cleaned , visited

②　以e结尾的动词直接加d：如　lived , danced , used

③ 以辅音字母加y结尾的动词要改y为i再加ed(此类动词较少)如　study – studied carry – carried worry –

worried (注意play、stay不是辅音字母加y,所以不属于此类)

④ 双写最后一个字母(此类动词较少)如　stopped

B、不规则动词(此类词并无规则，须熟记)小学阶段要记住以下动词的原形和过去式：sing – sang , eat – ate ,

see – saw , have – had , do – did , go – went , take – took , buy – bought , get – got , read – read

,fly – flew , am/is – was ,

are – were , say – said , leave – left , swim – swam , tell – told , draw – drew , come – came , lose

– lost , find – found , drink – drank , hurt – hurt , feel – felt

(3)一般将来时：

基本结构： ①be going to + do;

②will+ do. be going to = will

I am going to go swimming tomorrow(明天). = I will go swimming tomorrow.

(4)现在进行时: am,is,are+动词现在分词

动词现在分词详解 动词的ing形式的构成规则：

① 一般的直接在后面加上ing , 如doing , going , working , singing , eating

② 以e 结尾的动词，要先去e再加ing　，如having , writing

③ 双写最后一个字母的(此类动词极少)有：running , swimming , sitting , getting

第三部分：句法