Joy, what happened to the plane It ___ at midnight, but it didn’t land on the airport on time.

Surrounded by the armed police and having no way to escape ,the rebels (叛乱者) in Xinjiang Autonomous Region were forced to _____

．Our teacher is very busy.He is ________ in working out a teaching plan.

The money collected should be made good use _________the people in Sichuan Province who suffered a lot in the earthquake.

The computer was used in teaching. As a result, not only _____, but students became more interested in the lessons.[ ]