I opened the box and saw a piece of crystal snowflake and a greeting card with "Happy Birthday" in the blank paper.
我打开盒子并看见在白纸中有一片水晶雪花和一张写着“生日快乐”的贺卡。
2
I did, and nestled in white paper was a crystal snowflake with a card that said, "Happy Birthday."
我打开盒子，看见半隐半现在白纸中的是一片水晶雪花和一张写著“生日快乐”的贺卡。
3
In this paper, we divided the double frequency crystal into numerous small double frequency units and derived the harmonic power and the double frequency efficiency in each unit.