单选题 I ______ my homework when my mother came back.

单选题 The bridge ______ before last winter, but it hasn't been completed yet.

单选题 Look! The children ______ happily in the playground.

单选题 The letter ______ in English, so I couldn't read it.

单选题 The book ______ by the end of last month.

单选题 —Why didn't you come to the party yesterday? —Because I ______ an important meeting then.

单选题 The new technology ______ widely used in many fields since it was introduced.

单选题 By the time we got to the cinema, the movie ______ for ten minutes.