In fact fuels we burn and plant food we eat ______ their chemical energy in the form of heat.

_______ has been known that ______ other waste found in the ocean, the plastic  does not break down.

Ten professors______ the medical team to look into the cause of the disease.

Science and technology have __________ in important ways to the improvement of agricutural production.

 While I was making the model plane，my little nephew kept asking me questions with great ______ .