現(xiàn)在完成時(shí)及其它時(shí)態(tài)3

The friendly relations and cooperation between our two countries have been enhanced in the past few years.
     Up to the present everything has been successful.
     5. 現(xiàn)在完成時(shí)表示現(xiàn)在之前業(yè)已完成的動(dòng)作，雖然其效果或影響仍然存在但已不再繼續(xù)，但是有一些現(xiàn)在完成時(shí)的句子，在后面加上for+一段時(shí)間，則現(xiàn)在完成時(shí)的動(dòng)作就表示延續(xù)性。
     Thomas has studied Russian. (現(xiàn)在不再學(xué)俄語)
     Thomas has studied Russian for three years. (=Thomas began to study Russian three years ago, and is still studying it now. (同第2點(diǎn)用法第一個(gè)例句)
     6. 現(xiàn)在完成時(shí)還可以用來表示過去的一個(gè)時(shí)間到現(xiàn)在這段時(shí)間內(nèi)重復(fù)發(fā)生的動(dòng)作。
     We have had four texts this semester.
    現(xiàn)在完成時(shí)的“完成用法”和“未完成用法”
     1. 現(xiàn)在完成時(shí)的"完成用法"
     現(xiàn)在完成時(shí)的"完成用法"指的是動(dòng)作發(fā)生在過去某一時(shí)刻并已結(jié)束，但該動(dòng)作對(duì)現(xiàn)在產(chǎn)生了影響，與現(xiàn)在情況具有因果關(guān)系。