很多同學在大學英語四級考試中會存在一些誤區，認為語法不那么重要，其實英語語法是學習英語的指南，也會為我們大大地提高英語，以下是小編給大家整理的大學英語四級考試語法基礎：時態，希望可以幫到大家
1. 現在完成時、過去完成時以及將來完成時之間的區別
1) 現在完成時：
?、?構成：have / has +過去分詞
② 語法意義及要點：
a. 現在完成時表示一個過去開始的狀態或動作持續到現在并可能繼續持續下去，常同表示一段時間的狀語連用。如so far， up to now， since， for a long time等。
--he has worked as a teacher for many years.
--up till now， nothing has gone wrong.
b. 現在完成時表示一個過去發生的對現在仍有影響的動作或事件。常與不確定的過去時間狀語連用，如yet， just， before， recently等;也同表示頻度時間狀語連用，如often， ever， never， sometimes， several times等;還可同包括現在時間在內的時間狀語連用，如now， today， this morning等。但不能同特定的過去時間狀語連用(last year ， in 1997等)。
--i have never learned japanese before.
--we have been quite busy lately (recently)。
c. 在時間或條件狀語從句中，當表示將來完成時的意義時，要用現在完成時來代替將來完成時。
--we’ll start at 5 o’clock if it has stopped raining by then.
--i shall go to see you when i have finished my homework.
note： 行為不能持續的瞬間動詞(instantaneous verb)， 如arrive， begin， come， go， start， leave， die， join等通常不能用于這一語法意義，即該類動詞在現在完成時中不能與表示一段時間的狀語連用。
--he has joined the army for five years. (誤)
--he has been in the army for five years. (正)
2) 過去完成時：
① 構成：had +過去分詞
② 語法意義及要點：
過去完成時表示某一動作或情況發生在過去某一時刻之前并持續到該時刻。
--david and jenny had known each other for a long time before their marriage.
--they had got everything ready before the party began.
note： 與現在完成時截然不同的是過去完成時可以與表示具體過去的時間狀語連用。
--he said that he had seen her the day before yesterday.
3) 將來完成時：
?、?構成：shall / will + have +過去分詞
② 語法意義及要點：
將來完成時表示某一動作在將來某一時刻或將來某一動作之前已經完成或發生。
--he will have graduated from high school before his next birthday.
--the shop will have closed already before you get there.
2. 哪些動詞不能用于進行時
1) 表示狀態的動詞，如be， seem， appear， become， get等。
he is being a used-car dealer.(誤)
he is a used-car dealer.(正)
she is seeming always about to smile.(誤)
she seems always about to smile.(正)
2) 表示感官感覺的動詞，如see(看見)， hear(聽見)，feel(感覺出)， taste(嘗出)，smell(聞到)等。
the medicine is tasting bitter. (誤)
the medicine tastes bitter. (正)
i was seeing a car passing by our house. (誤)
i saw a car passing by our house. (正)
3) 表示擁有的動詞，如have， own， possess， belong， contain， hold等。
he is owning a luxurious car. (誤)
he owns a luxurious car. (正)
the book is belonging to her. (誤)
the book belongs to her.(正)
4) 表示思想狀況、態度的動詞，如believe， think， know， understand， agree， approve， consider， expect， forget， guess， hesitate， hope， imagine， mean， realize， remember， suppose， trust， want， wish等。
i’m thinking that he is right. (誤)
i think that he is right. (正)
i’m understanding your feelings. (誤)
i understand your feelings. (正)
5) 表示情感、愿望的動詞，如admire， appreciate， care， enjoy， like， love， hate， detest， regret等。
he is loving his daughter very much. (誤)
he loves his daughter very much. (正)
i’m regretting to say we cannot come. (誤)
i regret to say we cannot come. (正)
3. 時態的呼應
時態的呼應又稱時態一致(sequence of tenses)，指的是某些從句里的動詞謂語時態必須和主句里的時態保持一致。
如果主句里的謂語動詞是過去時態(過去時或過去完成時)，那么從句的謂語動詞時態也相應地要用過去時。時態的呼應主要發生在間接引語和賓語從句中，但其他從句有時也存在時態一致的問題。
--he explained that he had learned chinese for many years.(現在完成時變為過去完成時)
--he said he had been collecting materials on that subject for a long time.(過去進行時變為過去完成進行時)
--he told me that they would have completed that project by the end of the year.(將來完成時變為過去將來完成時)
雖然主句用了過去時等，如果從句表示的是科學真理、客觀事實或某人(物)的經常性特點時，其時態可以不必遵守時態呼應的規則而仍用一般現在時。
--galileo proved that the earth revolves round the sun.
--the teacher told the students that knowledge is power.
如果從句中有一個表示絕對過去時間的狀語，就不必把一般過去時變為過去完成時。
--he said that he joined the red army in 1933.
