外研版八年级下册M2语法

2、现在完成时态的标志现在完成时态在我们的语言运用过程中，常会发现句中带有以下四类标志性的副词或副词短语，我们把它称为现在完成时态的标志：

1）. never，ever，just，yet，before，already ,ever since then

2).some/many times，once，twice，three?..times

3).so far，recently，lately，these days/weeks/months/years; (in) the last /past few days/months/years

4).for+ 时间段，since+时间点， how long

例：①.i h**e already finished my homework． ②my father has gone to shanghai three times.

③i h**e learned about 2000 english words so fartom has been dead for two years.

3、当句中有for+时间段，since+时间点，how long 时，要求：h**e（has） +过去分词（动词必须是持续性动词)非持续性动词不能直接和for 或since 连用，但我们可以找一个相应的持续性动词或动词短语来替换这些非持续性动词。

4、重点标志for/since；already/yet；ever/never的区别

.for/since的区别 for后常跟一个时间段，如for three years, for half an hour等。 since 作介词，后面可以接一个时间点，如since 1980；也可以接“一段时间+ago”，如：

since three years ago, since two months ago等；since 还可用作连词，引导一个过去时态的时间状语从句，如：we h**e known each other since we went to college.

.already/yet的区别 already用于肯定句中，可放句首、句中和句尾。yet用于否定句或疑问句中，且常放在句尾。

. ever /never的区别 ever意为“曾经”,常用句型h**e you ever...其否定回答常用never。

5、句型 1）.h**e/has been to 意为“去过。地方”(已回来) h**e/has gone to 意为“去。地方了”(还没回来)

注意：①当某地是地点副词时应省略介词to，常见地点副词有here, there, where, home, abroad 等。

h**e/has been to, h**e/has gone to不能与for+时间段、 since +时间点、how long短语共存于同一句子中，因为been to 或gone to 是非持续性动词短语。如果要与一段时间连用，可使用其对应的持续性动词短语。例：

he has been to the usa since two years ago.(改错) he has been in the usa since two years ago. i h**e gone to this school since i move here.

(改错) i h**e been at this school since i move here.

where is sb? 回答常用gone to 例： 1)where is d**id?

he has gone to the usa. 2)where is tom? he has gone to shanghai.

2).it is + 一段时间+since+(一般过去时从句)