—May I go out tonight?—Of course you can, _____ you promise to be back before 10 o’clock.
With our class teacher _______into the class-room, immediately attracting our attention.
As we all know, improving one's reading ability _______ speed and comprehension.
You _______things about. Look, what a mess in your room!
As far as I am concerned, English can be _______a useful tool rather than just a language.
They really have a great time too, designing everything, drawing the blue prints, _______the angles(角度)and so on.