Finding Authentic Video Pronunciations...
Scanning thousands of native English clips with synchronized subtitles and exact timestamps.
Pronunciation Guide
Loading video player...
They uncovered evidence of its high-pressure and high-temperature beginnings — so high that some of the minerals within the glass, like those dark streaks of cristobalite,
couldn’t have possibly formed from ordinary happenings on Earth.
They found chemical traces that suggest bits of iron from within the gem weren't from our planet.
Listen to native speakers pronounce “couldn” in real conversational contexts with synchronized timestamps and subtitles.