初中英语语法动词八种时态详解：现在完成时
<p> 对于初接触现在完成时的人来说，往往会产生一种茫然，因为它似乎与一般过去时相似。那就是，这两种时态描述的动作都始于过去。其实不然，现在完成时主要表示，发生在过去的动作延续到现在刚刚完成、或许还要延续；侧重于这个动作对现在带来的结果、产生的影响、积累的总和等等。而一般过去时则只不过是表示动作发生在过去的什么时候。弄清了这一区别，就很容易理解现在完成时了。它主要适用于下面的几种情况：</p><p> 1)表示截止现在业已完成的动作</p><p> <span word="By">By</span> <span word="now">now</span>, <span word="I">I</span> <span word="have">have</span> <span word="collected">collected</span> <span word="all">all</span> <span word="the">the</span> <span word="data">data</span> <span word="that">that</span> <span word="I">I</span> <span word="need">need</span> 。到现在为止，我已收集到了我所需的全部资料。</p><p> <span word="She">She</span> <span word="has">has</span> <span word="read">read</span> 150 <span word="pages">pages</span> <span word="today">today</span> 。她今天已看了150页。</p><p> <span word="We">We</span> <span word="havent">havent</span> <span word="met">met</span> <span word="for">for</span> <span word="many">many</span> <span word="years">years</span> 。我们已多年没见了。</p><p> <span word="They">They</span> <span word="have">have</span> <span word="developed">developed</span> <span word="a">a</span> <span word="new">new</span> <span word="product">product</span> 。他们研制成功了一种新产品。</p><p> 2)表示发生在过去而对现在产生影响、带来结果的动作</p><p> <span word="Have">Have</span> <span word="you">you</span> <span word="had">had</span> <span word="your">your</span> <span word="dinner">dinner</span>? 你吃晚饭了吗？</p><p> <span word="She">She</span> <span word="has">has</span> <span word="been">been</span> <span word="to">to</span> <span word="the">the</span> <span word="United">United</span> <span word="States">States</span>. 她已去美国了。</p><p> <span word="You">You</span> <span word="have">have</span> <span word="grown">grown</span> <span word="much">much</span> <span word="taller">taller</span>。你长高了许多。</p><p> 3)表示过去发生的动作持续到现在，并可能还要延续</p><p> <span word="It">It</span> <span word="has">has</span> <span word="been">been</span> <span word="five">five</span> <span word="years">years</span> <span word="since">since</span> <span word="he">he</span> <span word="joined">joined</span> <span word="the">the</span> <span word="army">army</span> 。他参军五年了。</p>
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