The biggest whale is ______ blue whale, which grows to be about 29 meters long—the height of ______ 9-story building.
Videos, recordings and other learning aids are usually used __________ textbooks in language learning.
The student always asks his teacher __________ questions.
—Was it under the tree __________ you were away talking to a friend?—Sure. But when I got back there, the bike was gone.
Whatever he explained, he couldn't __________ the policeman that he was innocent.
Hearing the news, he rushed out, ______ the book on the table and disappeared into the distance.