He was puzzled by this phenomenon. He began to try every approach _________ the best way of working it out.
Three-fourths of the surface of the earth___sea.
If these trousers are too big, buy a smaller___.
—— Did you find your pen this afternoon? —— No, I didn’t find_____, but I’ve bought_____.
His “Selected Stories”_____first published in 1990.
Tom’s and John’s_____came to London last week.