Have you ever wondered why some of the smartest students in your class sometimes ________ failing exams?

f us, if we know even a little about where our food comes from, understand that every bite put into our mouths was alive.

I wonder____ she will come back or she will go straight to Beijing.[ ]

________ production up by 50%, the factory has another wonderful year.

He couldn’t ______ the fact that the money was found in his house.