如下 为什么填sing

如下 为什么填sing I often hear John (sing/singing/to sing)in his room.为什么这里要填sing i heard he （）（sing）at that time.为什么填was sing Every day we see him ___ (sing)happily.填Sing还是singing,为什么? Lucy is good at ___(sing).这个怎么填,为什么? I heard him ____ (sing) when I passed his room该填什么?为什么这样填? Let's practice____together. A.sing B.to singLet's practice____together.A.sing B.to sing C.singing D.sings填哪个?为什么?谢谢各位大神了! In spring,we can hear birds -----(sing) in the trees应该是填sing 还是singing呐老师说是填singing的这是为什么呢? I often hear her _(sing) in the morning ,填什么?为什么 They often sing and dance_____(happy).并解释为什么这样填, Can you ___(sing)the song litter Star?NO ,I can't.怎么填,为什么? I'd like-------(sing) a song for me visitors.填入合适的词,怎么填,为什么? （sing）l can the song l like 写出为什么填这种形式 we heard the girl _(sing)at this time yesterday ,中间填?为什么? （sing）l can the song l like 写出为什么填这种形式 they are ( )an english song 里面填sing里面填sing还是sing的现在分词 who can ___(sing) this song 填sing? she likes后面能不能填sing