Decide if the tenses in these sentences are correct or not. If not, correct them.
a. They are talking since 8 o'clock so it must be something important.
b. I have this computer for three years and it works very well.
c. We have seen a lot of films recently and think 'Kill Bill' is the worst.
d. We haven't talked for ages! How are you?
e. I've been patient. I was waiting for six weeks, but I can't any longer.
f. How many letters have you received so far?
g. When have you seen her?
h. I have cleaned the house since the morning and I haven't finished yet.
i. We are neighbours for a long time.