六.現在完成進行時：have / has + been + 現在分詞
    1.表示從過去某時開始發(fā)生，一直延續(xù)到現在且可能延續(xù)下去的動作。(將此定義讀 5遍)
    I've been waiting for an hour but she hasn't come.
    He has been running after her for 8 years.(run after: 追求)
    2.表某種感情色彩。
    I've been wanting to see you for so many years.
    Who's been telling you such nonsense.
    釋惑要點：現在完成時與現在完成進行時的對比：
    現在完成時強調“結果”，而完成進行時強調“動作的延續(xù)”。
    I have thought of it.(我已想到了這一點。)
    I have been thinking of it.(我一直在想這一點。)
    Jim has painted the door.(杰姆已將門油漆過了。)
    Jim has been painting the door.(杰姆一直在油漆門。)
    練習：
    1. They ________ us since five o'clock this morning.
    A. are helping B. have been helping
    C. have been helped D. have helped
    2. I ________ the book the whole day, yet I haven't finished it.
    A. have been reading B. have read
    C. am reading D. had been reading
    3. Please come in. We ________ about your paper.
    A. talk B. had been talking
    C. have been talking D. would have talked
    4. Such natural resources as coal and petroleum ________.
    A. gradually are exhausted B. are being gradually exhausted
    C. have gradually exhausting D. have been exhausting gradually
    5. It ________ almost every day so far this month.
    A. is raining B. rained C. rains D. has been raining
    用所給動詞正確時態(tài)填空。
    1. You should go to bed. You ________ (watch) TV for 5 hours.
    2. I ________ (write) letters since breakfast.
    3. I ________ (write) 3 letters since breakfast.
    4. Sorry, but Mr. Smith ________ (leave) for Beijing.
    5. I ________ (look) for him everywhere, where can he be?