Affirmation; Positive; Conducive to development (as opposed to "negative", often used in abstract things): play a positive role. Think positively.

2. Bohr [Edie N]?

The limit that can't be exceeded in degree: I am extremely happy.

3. Polar circle [jí quān]?

A circle formed by two parallel lines of 66 34' on the earth. It is called Antarctic Circle in the southern hemisphere and Arctic Circle in the northern hemisphere. They are the dividing line between temperate zone and frigid zone.

4. Extreme value [jí li dang]?

Medically, it refers to the maximum dose of drugs that patients are allowed to use in a certain period of time.

5. Tai Chi?

Terminology of China's ancient philosophy. Specify the origin of everything. Book of Changes: "It is easy to have Tai Chi, that is, two instruments are born, two instruments are born with four images, and four images are born with eight diagrams."