She turned the radio on at 7.30. She was still listening to it when her mother came home50/50Mark the letter A, B, C or D on your answer sheet to indicate the sentence that best combines each pair of sentences in the following questions. She turned the radio on at 7.30. She was still listening to it when her mother came home at 9.00She has been listening to the radio at 7.30She had been listening to the radio since 7.30She has been listening to the radio after 7.30She had been listening to the radio by 7.30Giải thíchĐáp án B