—What about the student in your class, Mr. Wang?—The doctor said that ________ sleep caused him poor memory and poor concentration.
—What do you have for breakfast? —I often have ________ or ________.
My school isn't far from here. It's only ________ walk.
— Who is in the reading room? The lights are all on.— ___________.
The conference has been held to discuss the effects of tourism _______ the wildlife in the area.
He went out without an umbrella , __________ in the rain.