C30 Difficulty

Chu Dong frowned. It wasn't hard to make glasses, but it wasn't easy either.

It's hard to make materials.

This was a primitive society, and he didn't know if he could still find the glass, the so-called quartz.

If it wasn't here, then he wouldn't be able to make these glasses.

Seeing Chu Dong's changing expression, Na Xin's heart also relaxed.

"I do have a way