1) Kate has been watering the flowers for forty minutes.
Kate has watered half of them.
2) Jack has been reading humorous stories since 2 o'clock.
Jack has read three stories.
3) Helen has been doing the shopping for an hour.
Helen has bought ten books.
4) Bill has been writing the letters since 5 o'clock.
Bill has written two letters.
5) They have been building the houses since 2006.
They have built five houses.
6) Susan has been translating the texts for 3 hours.
Susan has translated four texts.
7) Nick is tired - he has been watching videos since 2 o'clock.
Nick is tired - he has seen two films.
8) I have been learning English idioms for 20 minutes.
I have learnt seven idioms.
9) R-B has been eating sweets since morning.
R-B has eaten 100 sweets.
:)