.At the beginning of class, the noise of desks ____ could be heard outside the classroom.
Such a grammar mistake is __________ among the beginners of English study.
A person's __________ body temperature is about 37℃.
The program, __________ at improving the students' ability of listening and speaking, will surely be a success.
He didn't answer, with his gun __________ at David.
Teachers are now aware of the difficulty that some students have __________ attention.