--- Why did you laugh just now?--- John wanted to tell us very funny joke, but he forgot end himself.
_____ great fun it is to make a snowman in winter.
The flight to London wasbecause of the heavy snow.
Tom is weak in physics. He always feels _______ before he takes a physics test.
Ann is a careful girl. She always goes over her exercises to____ there are no mistakes.
To be healthy, one must have at least _____ sleep every day.