写省略句（英语）1.Jack must have playing football and must have been

写省略句（英语）1.Jack must have playing football and must have been 写出下列句子的省略句（英语）1.Jack must have playing football and must hav 句子省略This head must have been found in Classical times and ca 关于must have been MUST have been done must have been must have/ must have been的区别 must have been done must have done must have been done/must be done 在英语里coms been、must been和may been和come have been、must have be must not have been;could not have 英语中,must have been 和 must have +过去分词,有什么区别