I … from her once since she went away. 
have heard
have been hearing

I … for seven hours. 
have been walking
have walked

She … dozens of students but she has never met such a hopeless class before. 
have been teaching
have taught

She … . Somebody else ought to drive. 
has drunk 
has been drinking

She … since eight o clock. It is time she woke up. 
has slept
has been sleeping

We sandwiches for the party all the afternoon. 
have been making
have made

She … in this school for three years. 
has taught
has been teaching

I … for car keys but I have not found any. 
have looked
have been looking

It … for two hours and the ground is too wet to play. 
has rained
has been raining

I … for her for six years and she has never said Hello to me. 
have worked
have been working