13.Because they hadn’t booked a room in advance, there were _____ left when they arrived at the hotel.
---Did you remember to take the key to Tom? ---Yes, I gave it to him ________ I saw him.
It is ________ world of wonders, ________ world where anything can happen.
Father ________ for London on business upon my arrival, so I didn’t see him.
The boy’s dream was to have his own laboratory ________ to try out some of his own ideas.
There is a common belief among them ________ rubbish can should be put to good use.