While____the dog,you should take care not to____.Otherwise,it may be dangerous to strangers.
—— Where’s Jack? —— I think he’s still in___bed, but he might just be in___bathroom.
Which is_____country, Canada or Australia?
Alexander Graham Bell invented_____telephone in1876.
Beyond_____stars, the astronaut saw nothing but_____space.
Alice is fond of playing___piano while Henry is interested in listening to___music.