Nobody but two boys _________ late for class yesterday,
- Could you tell me_______?- Every four years.
We carefully compared the result of the first experiment with_______ of the second one.
_______ he is very young, _______ he knows a lot about how to be healthy.
Chinese students must_______ their hands first and then _______ to speak in class.
Simon usually plays_______ guitar on Sunday morning and plays_______ chess on Sunday afternoon.