_____Friday afternoons,many students are sleepy after a long week of classes. A.In B.On C.At
----- Your English is very good, who taught you? ----- Nobody. I taught _____.
_____ he is ill, _____ he still goes to work.
-----_____ do you exercise? -----Once a week.
Which is _____, the sun or the moon?
Lily and Lucy are twins, they _____ good girls, they often help others.