The scientists are trying to ___ natural energy to decrease air pollution.

When the book, Twilight, was first _____, it was immediately well received by readers. [ ]

You can hardly find a ______ comfortingfilm than “Slumdog Millionaire” to encourage people in a time of economiccrisis

He didn’t go to the lecture this morning, did he—_____.Though he wasn’t feeling very well.

Excuse me. ________ is the sports center from here—About five kilometers.