"We never eat red meat, " Tyler tells me in the Impala, and he can't use chicken fat or the soap won't harden into a bar.
Plaque needs to be removed through a daily oral care routine which includes brushing and flossing or the plaque will harden into tartar (or calculus).
Drinking in Japan is a crucial social and professional lubricant in a country where ritualized courtesies can easily harden into walls, and Bob, a teetotaler in college, had successfully adapted.
Melted metal is poured into a mold to harden into shape.
