My father goes to work ______ every day.A. by a bikeB. in a bikeC. on a bike
Students should pay attentions to ________ the teachers in class.
-- _________ go to the cinema together with me? -- Good idea!
Which of the following organizations is not a charity? ___________.
This problem is so tough that only______ students can solve it.
Although you have lots of difficulties, you must ______your work.