Being silent is also language, but it's not known by heart...

沉默也是冷冷的语言，只是自己的心永远听不见。

youdao

You must keep repeating the lines until they are known by heart.

你必须反复朗读这几行，一直到能背诵为止。

youdao

All had suffered a type of heart attack known as an ST segment elevation myocardial infarction, caused by a prolonged period of blocked blood supply.

他们都遭受ST段抬高心肌梗死(STEMI)的心脏病发作，是由于长期血管阻塞引起的。

youdao

Follow the path known by heart, down to the wide-open fields.

NPR: What's in a Song? 'Twilight'

Diadexus drew headlines last month when it helped identify what may be a new risk factor in heart disease: a little-known protein produced by the body that can double the risk of heart attacks.

FORBES: Divining Disease

Mr Koizumi, sometimes known as Lion Heart, may gain popularity by roaring at the Russian bear.

ECONOMIST: Japan and Russia