(届北京市海淀区高三下学期期中练习英语试卷)You cannot take back your words ______ they are out of your mouth.
_____ of the students who took part in the military training is 1450.
_____ the early bus, Tom got up much earlier than usual that morning.
The English teacher told us this morning that we _____ an exam at the end of this month.
Many of your classmates dislike having to stay up late doing their lessons, _____?
The most important thing is to keep _____ when you get into difficulties.