People with low Vitamin D level are more susceptible to infection.

维生素D含量比较低的人更容易生病。

youdao

Are you willing to compete at the Ph. D. level?

你愿意在博士级别竞争么？

youdao

Are you willing to compete at the Ph. D. level?

你愿意在博士级别竞争么？

youdao