Young people must be ready take new challenges .
______ is said that our math teacher often does volunteer work on weekends.
I took the wrong train _______. I didn’t even know it until half an hour later .
The mobile phone has influenced people’s life a lot since it ________.
--- I have trouble _______ my new computer. ---Don’t worry. I’ll show you how _______it.
–Do the Smiths live next to you? --No, but they____.