根据所给的中文和括号内的语法提示, 把下面句子翻译成英语,写在答题卷相应的横线上。
我觉得很奇怪他睡得那么少却能够干得那么卖力。（宾语从句）
I find ______ ________ ______ he is able to work so hard with so little sleep.
这两姐妹一定是吵架了，因为她们互不理睬。(must have done)
The sisters _______ _______ _______ an argument, for they are no longer talking to each other.
那位老师和两个学生参加了会议。（主谓一致）
The ________ with two ________ ________ at the meeting.
是什么事使他不能参加我们的会议仍然是个谜。（主语从句）
_______ prevented him from _______ our meeting still ______ a mystery.
老师不用抬头看就已经知道是哪个学生在班上讲话。（V+ing 作宾语）
Without ______ ______ _______ her desk, the teacher already knew which student was talking in class.