語法結(jié)構(gòu)——時(shí)態(tài)

一般現(xiàn)在時(shí)表示現(xiàn)在、經(jīng)常或習(xí)慣的動(dòng)作或狀態(tài)和普遍現(xiàn)象、常識(shí)或客觀真理；一般過去時(shí)用于過去某一時(shí)間內(nèi)發(fā)生的或過去習(xí)慣性的動(dòng)作或狀態(tài)；一般將來時(shí)表示將要發(fā)生的動(dòng)作或存在的狀態(tài)，將來打算做的事情；現(xiàn)在完成時(shí)表示過去發(fā)生的動(dòng)作造成目前的結(jié)果和對(duì)現(xiàn)在造成的影響或表示從過去延續(xù)至今的動(dòng)作、狀態(tài)和習(xí)慣等；將來完成時(shí)表示將來某時(shí)之前業(yè)已完成或發(fā)生的事情；過去完成時(shí)表示過去某時(shí)間之前已經(jīng)發(fā)生的動(dòng)作或狀況，即過去的過去。注意每一種時(shí)態(tài)與其他時(shí)態(tài)的交叉使用情況。英語共有十六種時(shí)態(tài)，其表現(xiàn)形式如下(以study為例)：
    一般時(shí)
    進(jìn)行時(shí)
    完成時(shí)
    完成進(jìn)行時(shí)
    現(xiàn)在
    study
    studies
    am studying
    is studying
    are studying
    have studied
    has studied
    have been studying
    has been studying
    過去
    studied
    was studying
    were studying
    had studied
    had been studying
    將來
    shall study
    will study
    shall be studying
    will be studying
    shall have studied
    will have studied
    shall have been studying
    will have been studying
    過去將來
    should study
    would study
    should be studying
    would be studying
    should have studied
    would have studied
    should have been studying
    would have been studying