—— Why do you decide ____ Beijing for vacation?——Because I want to visit the Great Wall.
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____.
--- Would you like to play computer games with me?--- Sorry, I have ________ playing them.