just now I heard students 【singing】in the classroom .为什么用singing,而不用sing?just now I heard students 【singing】in the classroom .为什么用singing,而不用sing?

I heard someone_____Beijing Opera just now 区别：i have just heard the news和i heard the news just now i heard lucy sing just now 变被动语态 I heard someone______(sing) just now.横线上填什么? I heard some children __(sing) a song just now . 为什么这里不要还原to?I heard the boy singing just now.The boy was heard singing just now. I feel very_(frighten).I heard a_(frighten)noise just now. 翻译英语被动句 I HEARD HER SING THE SONG JUST NOW SHE WAS HEARD TO SING THE SONG JUST NOW 翻译 I heard Amy singing in the next room just now怎么改被动语态? I heard her___ in the next room just now.A sing B singing I heard someone _____(knock /knocking) at the door just now .横线上应填什么?为什么 I heard a bird s____in the big tree outside just now. 英语连词成句 someone call my i name on heard the just now plaground 将I heard Amy singing in the next room just now.改成被动语态Amy __________ ____________ ____________ in the next door by_____ just now. I heard Amy singing in the next room just now.(改为被动语态)Amy ( )( )( )in the next room by ( )just now.急用!PLEASE! I heard him_____in the next room just now.A singing B.sing请问选哪个正确,为什么?此句有just now 还能用singing吗？ I heard the birds____(sing)in the forest just now 请问这里用sing 还是singing呢?和just now 有关系么? ---I heard you talking to somebody just now .---Oh,I___to myself .A was just talking B just talked 为什么选A?为什么不选B?