However, highly optical pure PLA could easily crystallize leading to the difficulty in preparing material with one or two dimensional orientational ordering.

但是纯态的聚乳酸容易结晶，难以制备在一维和二维取向有序的材料。

youdao

But popular groups not quite big enough to make the "Rock Band" playlist are also preparing material for the do-it-yourself upload store, including Creed and Evanescence, each of which has sold tens of millions of albums in the past decade.

WSJ: MTV Games Seeks Buzz for 'Rock Band'