Test and analysis: (1) According to the food source analysis of various nutrients, rice mainly contains starch, which belongs to sugar; Braised pork mainly contains oil and protein, sweet and sour fish mainly contains protein, sparerib soup mainly contains protein, water and inorganic salts, and calcium-containing milk mainly contains protein and calcium. Therefore, vitamins are still lacking, and vegetables should be supplemented.

(2) Most of calcium exists in human bones and teeth, so that bones and teeth have hard structural support. Teenagers will suffer from rickets and dysplasia due to calcium deficiency, while the elderly are prone to osteoporosis and fractures. Children and teenagers are in the stage of growth and development, and they need more calcium than adults, but they don't eat a lot of calcium tablets, so they choose ②.

(3) From the classification and application analysis of materials, ① the iron pot is made of iron and belongs to metal material; ② Cotton apron is made of cotton fiber and belongs to natural plant fiber; ③ Synthetic rubber gloves are made of synthetic rubber and belong to synthetic materials.

Comments: Paying attention to health and caring for life is a hot topic in recent years, and it is also one of the hot spots in the senior high school entrance examination. Therefore, it is the key to solve the problem to master relevant knowledge and make a good knowledge reserve.