When _________ the office, I found the naughty boy _________ beside my desk, trembling.
Don’t be shocked if you realize a man ____ is actually a millionaire. Rich people are weird.
It is always not easy to live in a foreign country; ____ so if you can’t speak their language.
You can’t park here, sir. It is ____ for the ambulances only.
The only existing problem is ____ we can find this special wood in the forest in such a short time.
The reason why they failed the test was ____ they didn’t sleep at all the night before.