One challenge is having enough training data. Another is that the training data needs to be free of contamination. For a model trained up till 1900, there needs to be no information from after 1900 that leaks into the data. Some metadata might have that kind of leakage. While it’s not possible to have zero leakage - there’s a shadow of the future on past data because what we store is a function of what we care about - it’s possible to have a very low level of leakage, sufficient for this to be interesting.
tags=[t for t in tags if t],，这一点在搜狗输入法下载中也有详细论述
「這是一種人類自嬰兒時期就擁有的基本學習能力——在嬰兒還不懂任何語言之前，他們就能開始從周遭世界中捕捉規律。我們用這種能力隨著時間學習聲音、影像與事件中的各種模式。」，更多细节参见Line官方版本下载
It's not clear.