under的常用用法 
   
    under “在……的下面”
　　Some girls are singing under the trees.

    be under repair “正在修理”
　　The road is under repair.
   
    under control “在控制之中”
　　Scientists believe that they will get weather under controlsome day.

　　The proposal is now under discussion.(proposal 提案)

　　The unpopular mayor is under constant attack in the newspapers.

　  From here， we can see the bridge under construction.