It’s ten years since the scientist ____ on his life’s work of discovering the valuable chemical.

 David has a big house, which ____ eight rooms. 

________ has Steven Spielberg produced an emotionally engaging movie, but he manages to get the hero's image in every viewer's mind as well.

I didn’t pass the oral test, so I am not _____ the mood to tell jokes.

“Did you get a job?” “No, I ______, but it’s no use.”