1.現(xiàn)在完成時用來表示現(xiàn)在之前已發(fā)生過或完成的動作或狀態(tài),但其結果卻和現(xiàn)在有聯(lián)系,也就是說,動作或狀態(tài)發(fā)生在過去但它的影響現(xiàn)在還存在.

　　I have lost my wallet.(含義是:現(xiàn)在我沒有錢花了.)

　　Jane has laid the table.(含義是:已可以吃飯了.)

　　Michael has been ill.(含義是:現(xiàn)在仍然很虛弱)

　　He has returned from abroad. (含義是:現(xiàn)在已在此地)

　　2. 現(xiàn)在完成時可以用來表示發(fā)生在過去某一時刻的,持續(xù)到現(xiàn)在的情況,常與for,since連用.

　　Mary has been ill for three days.

　　I have lived here since 1998.

　　3. 現(xiàn)在完成時往往同表示不確定的過去時間狀語連用,如already, yet, just, before, recently,still, lately等:

　　He has already obtained a scholarship.

　　I haven't seen much of him recently (lately).

　　We have seen that film before.

　　Have they found the missing child yet

　　4. 現(xiàn)在完成時常常與表示頻度的時間狀語連用,如often, sometimes, ever, never, twice, on several occasion等:

　　Have you ever been to Beijing

　　I have never heard Bunny say anything against her.

　　I have used this pen only three times. It is still good.

　　George has met that gentleman on several occasions.

　　5. 現(xiàn)在完成時還往往可以同包括現(xiàn)在時間在內的時間狀語連用,如now, up to these few days/weeks/months/years, this morning/week/month/year, now, just, today, up to present, so far等:

　　Peter has written six papers so far.

　　Man has now learned to release energy from the nucleus of the atom.

　　There has bee too much rain in San Francisco this year.

　　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.

　　6. 現(xiàn)在完成時表示現(xiàn)在之前業(yè)已完成的動作,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)在完成時的句子,在后面加上for+一段時間,則現(xiàn)在完成時的動作就表示延續(xù)性.

　　Thomas has studied Russian. (現(xiàn)在不再學俄語)

　　Thomas has studied Russian for three years. (=Thomas began to study Russian three years ago, and is still studying it now.(同第2點用法第一個例句)