The twin towers fell down. It looked_____ a huge piece of chocolate had been melted down(溶化).
The mother often tells her son to be a good boy, warning him to _____ trouble.
This heavy rain made______ impossible_______ us to complete the task on time.
It____ ten years ______ I graduated from university.
--Your father is sleeping. Don’t ______, will you?--No, I won’t.
______ it is to have a cold drink after an _______ game!