现在进行时态结构:be+ v.ing 动词-ing 形式的变化规律: 一般情况下,动词后直接加-ing working buying saying 2. 以不发音的结尾的动词,去e加-ing taking having leaving 3. 以辅音字母+元音字母+辅音字母的重读闭音节, 双写末尾辅音字母,然后加-ing shopping sitting getting 4. 特殊变化 lie--- lying