6. Put the verb into the correct form of the present perfect simple or continuous.
a. T. F. Jones ___________________ (write) a new book. I must buy it.
b. We _____________________ (wait) for half an hour! Where’s the bus?
c. I ____________________ (send) him an email and I’m waiting for his replay.
d. They ____________________ (talk) on the phone for two hours!
e. I ______________________ (not work) with him before.
f. Sara _____________________ (ride) horses since she was five years old.
