Mike was ill yesterday,_______ he didn’t go to school.
if we sit near________front of the bus,we’ll have________better view.
The population of the world in 20th century became very much _________than that in 19th.
If you have lost a library book, you have to _________ it.
If anyone wants to say something in class, you ________ put up your hands first.
-- __________ you ________ your book to the library? -- Yes. I returned it yesterday.