1.   Cigarette makers say the ammonia is added to enhance flavor and body, not to increase the amount of nicotine absorbed.

2.   MTBE is added to enhance the octane content of gasoline.

3.   A steroid hormone was added to enhance the chances of the cells committing themselves to becoming bone.

4.   In recent years, however, and mostly in urban areas, high-octane fuel and mentholated spirits have been added to enhance potency.

5.   In recent years, however, and mostly in urban areas, high-octane fuel and mentholated spirit are added to enhance potency.

6.   In recent years, however, and mostly in urban areas, high-octane fuel and mentholated spirit have been added to enhance potency.