Letterboxes are much more in the UK than in the US, where most people have a mailbox instead.
I tried phoning her office, but I couldn't __________.
Jane is very popular because she is easy to __________.
__________ a strange plant! I've never seen it before.
Who do you think you'd like __________ with you, a boy or a girl?
— __________ Emily is in such a hurry? —I don't know. She might run to catch the bus.