If you load this class, Ruby will complain about "direction" and "speed" being unknown.

用Ruby加载这个class，解释器会提示我们它不知道“direction”和“speed”是什么。

youdao

Until now, though, the structure of this important class of proteins was unknown.

不过此前，研究人员还不知道这一重要类别蛋白的结构。

youdao

Until now, though, the structure of this important class of proteins was unknown.

不过此前，研究人员还不知道这一重要类别蛋白的结构。

youdao