---What’s your impression of the Great Wall?---Wonderful! Once ____ , it can never be forgotten.
A cough is usually nothing to worry about unless it lasts for ten days _____
Of the two coats, I'd choose the _____one to spare some money for a book.
I want to thank my friend John, without _____ help, I wouldn't have been saved.
— Look! Somebody _____the sofa. — Well, it wasn't me. I didn't do it.
_____ on folk tales, Mo Yan's novels become a mixture of fantasy and reality.