直到现在的

Only now did he understand the full complexity of the problem.

直到现在他才明白这一问题的全部复杂性。

Only small amounts of wurtzite boron nitride and lonsdaleite exist naturally or have been made in the lab so until now no one had realised their superior strength.

天然存在或者实验室制造的纤锌矿型氮化硼和朗斯代尔石数量少，直到现在，也没有一个人发现它们令人吃惊的硬度。