各种质量的恒星的演化，均以流体力学的时间尺度进行。
Evolution of stars of all masses takes place on a hydrodynamic time scale.
学会了看问题，就不会杞人忧天，就会研究各种质量改进办法。
Learn to look at problems, not to entertain imaginary or groundless fears, will study various quality improvement methods.
综述了干腌火腿中常见的各种质量缺陷以及防止这些质量缺陷的措施。
This paper reviews the main quality defects in dry-cured hams and their preventive measures.
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