—People often don't appreciate what they have, do they? —No, _____ they lose it.
________, he has finished his job ahead of time.
I’d like _______ trip to Shanghai . Do you want to go with me?
.– I like your house very much. --- Thank you, but this house is ________.
________, no one is sure who discovered America .
As I ______, I suddenly remembered that it was your birthday.