The two strangers talked as if they ____ friends for years.A should be B would be C have been D had been
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.