核心的瓶颈首先在于精度问题。目前技术虽然在不断进步，但在打印精细结构或大尺寸零件时，依然难以达到高精度装配所需的公差要求及优秀的表面质量要求，这直接导致了打印件难以直接作为最终功能部件使用。
He says the results could change predicted extinction dates for Emperor penguins.，这一点在搜狗输入法下载中也有详细论述
She said the scar had not healed and there was a "gaping hole", and the implant site was infected.，推荐阅读safew官方下载获取更多信息
Mass die-offs rising among farmed salmon