The book Diary of a Wimp Kid has been popular since it _____.
—Who is singing in the next room?—___________ must be Marie.
—TV says there will be a storm tomorrow.—___________, I planned to go climbing with my classmates.
Smile to the world, ___________ the world will smile back to you.
—What do you often pay attention to when you learn English?—___________.
The lady ________ dancing as a hobby in her sixties, and she is really good at it now.