Obviously,today only in very few countries do the citizens have the awareness of the impotrance of saving water and using awter peoperly;as a consequence,a vast amount of fresh water is wasted on a daily basis.这里的do the citizens是什么用法啊

do是助动词，当副词或副词词组移置到句首时，用以改变主语和动词的语序，即变成倒装语序。此句only in very few countries 放在句首，句子需用倒装语序，the citizens 是句子的主语。
例如；Not only does she speak Spanish,she also knows how to type.
So much did they eat that they could move for the next hour.
Realy did she request help but this was a matter of urgency.