According to Chinese traditional medicine, start of summer is a key time to moisten the heart.

中医认为，立夏是滋润心脏的关键时刻。

youdao

At the heart of the debate over illegal immigration lies one key question: are immigrants good or bad for the economy?

关于非法移民的争论的核心是一个关键问题：移民对经济是好还是坏？

youdao

Alec believes showing interest is the key to winning a girl's heart.

要赢得女孩子的芳心，关键是要表现出感兴趣。

youdao

The study subjects also saw their cholesterol levels - another key heart risk indicator - more than halved on average.

BBC: Smoking: The sex divide

Settling this debate once and for all will require large human trials to prove that lowering inflammation with a drug will reduce the frequency of heart attacks beyond what can be accomplished with existing classes of drugs (see: " Inflammation Is Key In Heart Attacks").

FORBES

Delta has remained mostly mysterious, but seems to play a key role in heart disease.

FORBES: Of Marathon Mice And Fat Men