正确理解词语 解释下列词语。
①正襟危坐：____________________________________________________________________
②诚惶诚恐：____________________________________________________________________
③鹤立鸡群：____________________________________________________________________
④藏污纳垢：____________________________________________________________________
⑤颔首低眉：____________________________________________________________________
⑥粗制滥造：____________________________________________________________________
⑦麻木不仁：____________________________________________________________________