Tags are very common in spoken English, and have many functions. One of the common functions is to start a conversation or help keep it going. The two basic rules about tag questions are:1  If the statement is negative, the tag must be positive.ags are very common in spoken English, and have many functions. One of the common functions is to start a conversation or help keep it going. The two basic rules about tag questions are:
The average cost for a community to fluoridate its water is estimated to range from approximately $0.50 a year per person in large communities to approximately $3.00 a year per person in small communities. For most cities, every $1 invested in water fluoridation saves $38 in dental treatment costs.55 âFor most cities, every $1 invested in water fluoridation saves $38 in dental treatment costs.â It can be calculated from these data that the average lifetime cost per person to fluoridate a water system is less than the cost of one dental filling.
A 16-ounce bottle of water costs about $1.50 at my local gas station. Buy a bottle of water five days a week, and you'll spend $30 a month and $360 a year. While it's not really free, water from your tap is much cheaper. If you hate the taste-and I do-you can buy a water-filtration system for as little as $20. Check out Consumer Reports' Water filters: green buying guide 2/12.