There are hundreds of visitors ___ in front of the Art Gallery to have a look at Van Gogh’s paintings.
Every device ______in the plane must be designed and made with great care so as to make sure that nothing goes wrong in operation.
He left home early only______he was late as he went a wrong way.
— Beijing or Shanghai? What did you mean? — We were talking about _______ go to college.
When he was a boy, he used to go there and watched _______.
Robert is said______ abroad, but I do not know what country he studied in.