US special envoy to NKorea arrives in Beijing for talks

What is the primary focus of the '2nd' concept introduced in the video?

• A scientific principle

• A historical event

• A new mathematical theorem

• A language rule

Which example best illustrates the '2nd' concept?

• A car accelerating

• A river flowing

• A plant growing

• A pendulum swinging

What is a key takeaway from the explanation of the '2nd' concept?

• It is universally applicable

• It is only relevant in specific scenarios

• It contradicts previous theories

• It is a newly discovered concept

How does the '2nd' concept conclude in the video?

• With a summary of its applications

• With a new hypothesis

• With a historical anecdote

• With a question for further research

What is the significance of the '2nd' concept in the broader context?

• It challenges existing paradigms

• It supports existing knowledge

• It is irrelevant to current studies

• It is a niche topic