Unit 17. Present perfect continuous (I have been doing) or present perfect simple (I have done)

A.
Study these example solutions:

B.

See Unit 18 for more information about the present perfect and how long?
C.
Some verbs are not used in the continuous form, for example know. You have to say have known (not have been knowing). For a list of these verbs see Unit 3b.
  
  
  
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