---How does Jack usually go to school? ---He_____________ride a bike, but now he_______________there to lose weight.
I think ____ of the materials I listened to at the beginning of the exam ____ easy.
A little boy wrote _____ “u” and _____“n” on the wall.
--- Why do you often take exercise? --- _____ me keep fit.
--- We went to see the man who was in hospital yesterday. --- __________.
If H2 burn in O2, we can get _____.