The respiratory system plays an important role in maintaining our internal environment at the proper level of oxygen, by bringing the right amount in.

呼吸系统的重要性在于,通过向体内输入适量的氧气,维持人体内环境中的氧平衡

耶鲁公开课 - 生物医学工程探索课程节选

The states are ceding many blocking powers, but in return for new ones from the federal level, particularly in higher education, the penal system and civil-service law.

ECONOMIST: German reform

The report suggested the A-level system in England be reformed to bring the system into closer alignment with the Scottish one, with a wider range and increased number of subjects.

BBC: Royal Society praises Scots education system

Instead, while the natural cannabinoids elevate the normal level of activity already going on in the system, rimonabant lowers it so the result is precisely the reverse of activating the receptor naturally.

CNN: Marijuana: The next diabetes drug?