2022年中考英語時態復習系列（六）現在完成時
現在完成時表示1）過去發生或已經完成的動作或存在的狀態對現在造成的影響或結果.（即它的＂完成用法＂）e.g. i have just cleaned the classroom. 2)過去已經開始，一直持續到現在的動作或狀態。注意：此時動作可能還要繼續。（即它的＂未完成用法＂）。 e.g. he has lived in beijing for ten years.
其結構是“have/has+過去分詞”。過去分詞的變化分規則與不規則兩種。規則變化與過去式相同，不規則變化需要另記。
它的否定句是在have/has后邊加not，變一般疑問句是把have/has提前。e.g. i have ridden a horse. i have not ridden a horse. have you ridden a horse?
它的時間狀語通常為already, just, yet, ever, never, before等。另外還可和since+表過去的時間點，for+時間段連用。
做題時常見錯誤如下：
一、易丟掉have/has
例：he taken (take) the medicine before.
答案：has taken
解析：have/has 為助動詞，起構成時態的作用，是不能省略的。我們可以這樣記：“現在完成時態中，have/has 不可缺�！�
二、have與has易用混
例：i has never heard (hear) of that before.
答案：have heard
解析：現在完成時與一般現在時一樣也有單三人稱的變化，當單三人稱作主語時用 has, 一般人稱作主語時用have.
三、延續性動詞與短暫性動詞易弄錯
例：she has left (離開) for 2 hours.
答案：has been away
解析：在肯定句中，與since或for引出的時間狀語連用的是延續性動詞，不能是短暫性動詞，但在否定句中短暫性動詞也是可以的。e.g. i haven't bought clothes for one year. 在此題中leave是短暫性動詞，不能與for+時間段連用，須把它改成相應的延續性動詞。如stop be over等。此題中leave要改成be away。這兩種詞的轉換是學習現在完成時需要注意的。
專項練習：
一、單選
1 you have _____ a tall young man.
a grown b grown into c grown us d grown up
2 he has ____ the watch for a year.
a buy b bought c have d had
3 has your brother _____ the dog?
a kept in b fed c fed on d kept on
4i _____this book for two weeks, i have to return it now.
a borrowed b have borrowed c kept d have kept
5 have you ever _____to the great wall? it's very beautiful.
a gone b been c went d go
6 her brother _____the party since 1978.
a joined b has joined c has been in d was in
7 the greens _____many places of interest since they came to china.
a will visit b visited c have visited d visit