The students should _________ when the teachers give the lessons.
Of the two American students, Mary is ____ one. I think you can find her easily.
-- Is there _____ in today’s newspaper?--No, there’s _____.
--Would you like some juice or milk?-- _____ is OK. I don’t mind.
We found ____ very easy to learn a foreign language well ____ the teacher’s help.
_____ mobilephone is not so expensive as _____, but it works well, too.