What does david smith mean by a “world city (aka global cities)” what role do they play in the global system?

Concepts of World City includes geographical dispersal of economic activities, increase the number of share for global firms, improvement of firms such as accounting, legal, public relations, programming, telecommunications, enhancement of production, maintain economic stability and improvement of the global network of affiliates.

Any time if 18 but would need the money

When two vehicles meet on a steep road where neither can pass: the vehicles going downhill must back up or simply must yield the right of way so it can pass : )