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.
On the other hand, some of us will barely blink an eye at picking up a few bottles of water from the same gas station. Here are the numbers: A gallon of gas costs around $3. If we assume a one-liter bottle of water from the store costs about $2.50, a gallon of the same bottled water should cost about $10.Water, life's most necessary substance, costs about three times more than gasoline when it comes in a plastic bottle.n the other hand, some of us will barely blink an eye at picking up a few bottles of water from the same gas station. Here are the numbers: A gallon of gas costs around $3. If we assume a one-liter bottle of water from the store costs about $2.50, a gallon of the same bottled water should cost about $10.