I hope I will not be called on in class as I am not yet ________prepared.

As we all know, health food usually doesn’t ____ too much fat.

Carbon dioxide, which makes a ______ between us and the sun, prevents heat from getting out of the atmosphere easily, so the earth is becoming warmer.

 ______ the warning message, more visitors might have been trapped in the flood. 

The boy’s bad behavior at school __________ his mother many sleepless nights.