??動詞時態(tài)是語法測試中一個很重要的方面。要掌握動詞時態(tài)，必須弄清每一時態(tài)的基本時間概念及基本用法；更要弄清句中以什么時態(tài)為基點，從而理解一個時態(tài)與另一個時態(tài)在同一個句子中的交叉使用情況。
??（1） 句中時態(tài)以現(xiàn)在時間為基點 句中時態(tài)以現(xiàn)在時間為基點，那么句子中可以相互搭配的時態(tài)形式通常有：一般現(xiàn)在時、 現(xiàn)在進(jìn)行時、一般將來時、一般過去時、現(xiàn)在完成時、現(xiàn)在完成進(jìn)行時等，但就時態(tài)的測試重點多在于現(xiàn)在完成時。
??如： You should have put the milk in the ice-box; I expect it ____ undrinkable by now.
A) became B) has become C) had become D) become
??句中第二分句中的時態(tài)基點為現(xiàn)在時（謂語動詞expect），句中時間短語"by now"表示"到現(xiàn)在為止"，暗示動作已完成，故答案為（B）。
??（2）句中時態(tài)以過去時間為基點，句中可相互搭配的時態(tài)通常有：一般過去時、過去進(jìn)行時、過去將來時、過去完成時、過去完成進(jìn)行時等。
??如：Whenever we visited them, they ____ television.
??A) have watched B) watch C) had watched D) were watching
??句子時態(tài)的基點為過去時間，那么在句中與之相搭配的時態(tài)，從四個選擇項的形式來看，有（C）和（D）。再根據(jù)whenever的詞意，可以判斷（D）為正確答案。
??（3）主要時態(tài)的時間狀語提示詞
??現(xiàn)在完成時： so far，by now，up to now，for，since，recently，lately，in the past few…，during the last few…，etc.
??過去完成時：by the end of＋過去的時間，by then，up to then，etc.
將來完成時：by the end of ＋將來的時間
??在四級語法結(jié)構(gòu)測試題中，以動詞時態(tài)為測試對象的大多是對現(xiàn)在完成時、將來完成時、過去完成時的測試。
??例3 By the end of this month, we surely ____ a satisfactory solution to the problem.
??A) have found B) will be finding C) will have found D) are finding
??答案是（C）。這里由by引起的時間狀語表示到將來某個時間為止，因此句子的謂語動詞需用將來完成時。
??例4 We ____ our breakfast when an old man came to the door.
??A) just have had B) have just had C) just had D) had just had
??答案是（D）。主句的動作發(fā)生在從句之前，從句的時態(tài)是過去時，因此主句應(yīng)用過去完成時。
??1．動詞時態(tài)
??1) By the end of this year all but two people ____.
??aa?have left?will leave?will be leaving?will have left
??2) She will come to call on you the moment she ____ her work.
??aa?has finished?finished?had finished?will finish
??3) You will hardly believe it, but this is the third time tonight someone ____ me.
??aa?telephoned?has telephoned?telephones?should telephone
??4) The company ____ a rise in salary for ages, but nothing has happened yet.
??aa?promised?is promised?is promising?has been promising
??5) Is it likely that the scientists ____ a cure for cancer by the year 2050?
??aa?will be discovering?are discovering?will have discovered?have discovered
??6) This is the second time I ____ your beautiful country.
??aa?had visited?visited?am visiting?have visited
??（1） 句中時態(tài)以現(xiàn)在時間為基點 句中時態(tài)以現(xiàn)在時間為基點，那么句子中可以相互搭配的時態(tài)形式通常有：一般現(xiàn)在時、 現(xiàn)在進(jìn)行時、一般將來時、一般過去時、現(xiàn)在完成時、現(xiàn)在完成進(jìn)行時等，但就時態(tài)的測試重點多在于現(xiàn)在完成時。
??如： You should have put the milk in the ice-box; I expect it ____ undrinkable by now.
A) became B) has become C) had become D) become
??句中第二分句中的時態(tài)基點為現(xiàn)在時（謂語動詞expect），句中時間短語"by now"表示"到現(xiàn)在為止"，暗示動作已完成，故答案為（B）。
??（2）句中時態(tài)以過去時間為基點，句中可相互搭配的時態(tài)通常有：一般過去時、過去進(jìn)行時、過去將來時、過去完成時、過去完成進(jìn)行時等。
??如：Whenever we visited them, they ____ television.
??A) have watched B) watch C) had watched D) were watching
??句子時態(tài)的基點為過去時間，那么在句中與之相搭配的時態(tài)，從四個選擇項的形式來看，有（C）和（D）。再根據(jù)whenever的詞意，可以判斷（D）為正確答案。
??（3）主要時態(tài)的時間狀語提示詞
??現(xiàn)在完成時： so far，by now，up to now，for，since，recently，lately，in the past few…，during the last few…，etc.
??過去完成時：by the end of＋過去的時間，by then，up to then，etc.
將來完成時：by the end of ＋將來的時間
??在四級語法結(jié)構(gòu)測試題中，以動詞時態(tài)為測試對象的大多是對現(xiàn)在完成時、將來完成時、過去完成時的測試。
??例3 By the end of this month, we surely ____ a satisfactory solution to the problem.
??A) have found B) will be finding C) will have found D) are finding
??答案是（C）。這里由by引起的時間狀語表示到將來某個時間為止，因此句子的謂語動詞需用將來完成時。
??例4 We ____ our breakfast when an old man came to the door.
??A) just have had B) have just had C) just had D) had just had
??答案是（D）。主句的動作發(fā)生在從句之前，從句的時態(tài)是過去時，因此主句應(yīng)用過去完成時。
??1．動詞時態(tài)
??1) By the end of this year all but two people ____.
??aa?have left?will leave?will be leaving?will have left
??2) She will come to call on you the moment she ____ her work.
??aa?has finished?finished?had finished?will finish
??3) You will hardly believe it, but this is the third time tonight someone ____ me.
??aa?telephoned?has telephoned?telephones?should telephone
??4) The company ____ a rise in salary for ages, but nothing has happened yet.
??aa?promised?is promised?is promising?has been promising
??5) Is it likely that the scientists ____ a cure for cancer by the year 2050?
??aa?will be discovering?are discovering?will have discovered?have discovered
??6) This is the second time I ____ your beautiful country.
??aa?had visited?visited?am visiting?have visited