(1) The Pearl River Delta is located in the southeast of Guangdong Province, at the lower reaches of the Pearl River, adjacent to Hong Kong and Macao, and across the sea from Southeast Asia. It is the "southern gate" of China.

(2) China's two special administrative regions are located on both sides of the Pearl River Estuary, of which the Hong Kong Special Administrative Region is located on the east side, and China's north-south Beijing-Kowloon railway line can directly reach here;

(3) The tertiary industry in Hong Kong and Macao is developed, among which gaming tourism is the pillar industry in Macao;

(4) The advantages of Hong Kong and the Pearl River Delta are complementary and mutually beneficial, forming a unique model of regional division of labor and cooperation.

So the answer is: (1) beads; (2) Hong Kong; Jingjiu; (3) gambling tourism; (4) "front shop and back factory".