Children in that kindergarten are sometimes asked to sit on their hands            ______listening to the teacher.

_____earth scientists understand how and why earthquakes happen, forecasts are usually inaccurate.

Double ovens are a good idea, especially ________ you are cooking several meals at a time. 

The seriously ill man thinks it doesn’t matter　　　he will die, but what matters much is how he lives. 

 _____ you have offered 50 yuan , you can telephone for 100 yuan.