(1) Rice mainly contains sugar; Braised pork mainly contains oil and protein; ; Sweet and sour fish mainly contain protein; Pork ribs soup mainly contains protein, water and inorganic salts. Calcium-containing milk mainly contains protein and calcium, and vegetables should be added.

(2) Children or adolescents may suffer from rickets or dysplasia due to calcium deficiency, while the elderly are prone to osteoporosis and fractures. Minors are in the stage of growth and development, and need to consume more calcium than adults, so they choose ②;

(3) The wok is made of metal, the cotton apron is made of natural plant fibers, and the synthetic rubber gloves are made of synthetic materials, so fill in ②; ①

So, the answer is: (1) sugar; Vegetable; (2)②; (3)②; ①.