【therearesomechildrenswimminginthepool这里的孩子正在游泳池游泳!我觉得正在游泳应该是beswimming,所以句子是therearesomechildrenareswimminginthepool但是这样句子里就出现了两个动词is似乎不对,但】

　　therearesomechildrenswimminginthepool这里的孩子正在游泳池游泳!我觉得正在游泳应该是

　　beswimming,所以句子是therearesomechildrenareswimminginthepool但是这样句子里就出现了两个动词is似乎不对,但therebe句型必须带be,所以疑惑了请求帮助