---Haven’t you heard of a person called Zhang Cunhao?---______. He is a famous scientist and won the 2013 Top Science and Technology Award.
-- ________ you tell me how to write it in English? -- I'm sorry, I can't.
Look! They ________ in the hallway.
Can you help me ________ my homework?
The teachers ________ on the blackboard with chalk in the future.
- ________ book is this? -- It's Mary's.