为什么I often hear the ____ of children playing happily downstairs 空格里填sound?voice B.noise C.sound D.throat魔方格说选sound.但是原因没说,我觉得voice和noice也都可以啊最好说明一下为什么voice和noice为什么错

I often hear her _____ (sing)in the next room last year.为什么不能用singing? I often hear her _(sing) in the morning ,填什么?为什么 I often hear him _____ ( sing ) in the next room.为什么答案上要求加ing? I often hear the little girl___(cry)in the morning I often hear him _____ ( sing ) in the next room. I often hear the song _____on TV.（sing） I often hear him ( ) in the room I often heard him ( ) in the room I often hear the little girl ___(cry)in the morning.hear后面要不要加doing? 为什么不填crying？？ I often hear the lonely girl sing in her room为什么中间用sing而不用sings啊 I often hear the sound of the violin______（come） from the park nearby .I hear the headmaster is going to london next week .为什么用hear.而不用hear of 或者hear from I often hear him sing the song in the room.变为被动语态 I often hear him sing the same song被动语态He ____ often ____ ____ sing the same song. I often hear him paly the piano at home.里面的那个play啊..为什么不要-s啊?!him不是第三人称单数么?!这样写什么意思啊?! i often hear from my brother who studies in __ university in Americaa:ab:anc:the 答案是什么,具体解释为什么其他选项不可以 I often hear her sing this songsing不用第三人称单数吗?为什么不是时间是I often hear her sings this song I often hear him（）in the next room.（sing） I often hear birds ( )in the morning?是填to sing 还是填singi