One of the children must have hidden it up.这是现在完成时吗?这个have仅仅

It must have fallen out of my purse.为什么要用现在完成时,不是已经掉过了吗? It must have been ten years ago we last wrote 现在完成时的句式,这歌词中, 请问:how could they have grown up healthily?是现在完成时吗?为什么不将have提 英语翻译I have hidden in the darkness of the place,waiting for t ____ must have witnessed the robbery.one of the passer-by/on The wallet must have been found by one of the villagers.(改为主 The wallet must have been found by one of the villagers改为主动句 i suppose _ must be one of the children 45.Because of the one-child policy,many children have proble 1.They have a son and a daughter.One of the children is good 英语填空题1.They have a son and a daughter.One of the children is 7年级、英语题目1.They have a son and a daughter.One of the children