现在完成时 vs 一般过去时
都讲过去的事，着眼点完全不同。
现完讲结果与影响；过去只讲时间点
要点
- 一般过去时只陈述过去的事实，与现在无关。
- 现在完成时强调过去的事对现在的影响。
- 有明确的过去时间状语时，只能用一般过去时。
- 问「做过了没有」用现在完成时，问「什么时候做的」用一般过去时。
- 标志词分两堆：already / just / ever / never / so far / up to now / in the past few years 走现在完成时；just now / the other day / yesterday / last week / in 2010 走一般过去时。
- have been to 去过（人已经回来）／ have gone to 去了（人还没回来）／ have been in + 地点 在某地待了多久。
- 与 for、since 连用时动词必须能延续，短暂动词要换成可延续的说法：buy → have，borrow → keep，die → be dead，join → be in / be a member of，come back → be back。
- It is / has been + 一段时间 + since + 一般过去时 是固定句型：It is three years since we left school.
例句
I have just finished reading this book.
我刚读完这本书。（强调现在读完了）
He went to the park yesterday.
他昨天去了公园。（只说过去的事）
Have you ever seen a panda?
你见过熊猫吗？（问经历）
I was born in 2010.
我出生于2010年。（有明确的过去时间）
He has gone to Shanghai, so you can't see him now.
他去上海了，所以你现在见不到他。
We have known each other since primary school.
我们从小学起就认识了。
易错提示
- 句中有 yesterday、last…、…ago、in 2010，一律用一般过去时。
- 现在完成时不能与明确的过去时间状语连用。
- 「I have bought the book for two years.」是错的，buy 只是一瞬间；要说 I have had the book for two years.
- 判断用 been to 还是 gone to，就看人回没回来：人不在眼前用 has gone to。