nail down (someone or something)
to make certain or sure of something
I am trying to nail down the exact time that the meeting will begin.
Moroccan Mint Tea
Green tea is rich in a powerful antioxidant that not only inhibits the growth of cancer cells but also kills cancer cells without harming healthy tissue. Green tea may also increase mental alertness, aid in weight loss, reduce LDL cholesterol, and protect the skin from sun damage. Seems like plenty of reason to enjoy a glass of this sweet, mint-scented tea every day.