fill in the blanks with the correct tense forms
a) your friends -- (wait) for you for over an hour.  where --  you -- (be) all this time?  you --(be) out for almost four hours.
b) she says that she --  (send)  the letter a month ago; but, so far, she -- (not receive) any reply.   she -- (thin) that her letter -- (be) lost in the post.