Tom, clean up the broken glass _________ someone walks on it.
Tony, mind your manners. Don’t _______ while others are talking.
The companies are working together to create they hope will be the best means of transport in the 21st century.
The hotel wasn’t particularly good. But I ____ in many worse hotels. A .was staying B, stayed C. would stay D. had stayed
Scientists are trying to develop a special material, _______ they will make use of in space.
The education of _______young is always _______ hot and serious topic in modern society.