It was just at the timethe bell rang he finished the last word in his composition.

es ________ on the PPT, Lee listened to the teacher ________.

Tom is ill. What’s wrong with him —Poor boy. His illness is the _________ of eating unhealthy food.

填入下面一段文字横线处的语句，最恰当的一句是（ ）专家表示，汞经常出现在我们的日常生活中，如果对含汞产品使用或处理不当很容易造成汞污染。 ，达到一定量便会对人体产生危害，严重的甚至会造成汞中毒。因此，建议定期进行汞含量检测，并掌握与汞相关的科学知识，做好汞污染的预防工作。

I a soccer ball and Sally a basketball.