"They do not understand."

Translation: 他们不明白。

[Nivkotzer]

I don't understand why the falling tone on bài...

[SebasGaravano]

Actually, chinese words that are composed of mor than 1 character tend to stress one of its characters. In this case, the stress is in the first character, so, unless you say the word really slowly and clear, this tone would be pronunced as a 0 tone. Here is another example:

认识
rènshi
ren4shi0

[JairoCaste19]

Ming2bai0

[JairoCaste19]

Shalom! Should be neutral.

[Drinc]

It's not a falling tone, it's no tone at all. The second syllable is unpronounced like in 妈妈 ma1ma.

I suggest using an app like Pleco to make sure the pronounciation is right.

[Shealyn24]

i said "ta men bu ming bai" and they said "ha! gatcha."

[SonOfASelkie]

Feel like “他们都不懂" should be allowed. 懂 is usually a valid substitute on Duolingo (had never been taught 明白 before Duolingo) so not sure why it failed me here.

[Lamar_DA_BOSS]

What is the difference between 明白 and 知道?

[JAndrzej]

明白 - to understand;
知道 - to know (something, not someone, because that would be 认识)