More and more people ________ square dance in China these days.  ( 对……感兴趣 )
_______ is becoming more and more serious today. It’s bad for our health.   ( 空气污染 )
My favorite teacher Miss Li likes wearing sweaters, and usually there is a _______ on her face.  ( 甜美的微笑 )
We should form a good habit of _______ the rubbish at anytime.   ( 捡起 )
Some students always discuss their homework __________.   ( 通过电话 )