You _______ ever saw computers years ago, but now they are everywhere.

Tom, I’m watching a football match. What about you? —.[ ]

Have you returned the book to the library _______?—Yes, I have _______ retuned it.

Excuse me, is there ______ book by Mo Yan? -Yes. It’s on ______ bookshelf over there.

______ is Yiwu River?—About forty kilometers.[ ]