(1) According to the information in the title, a. Promoting circular economy can solve the problems of energy crisis, resource shortage and environmental pollution in China, which is correct.

B. Chemical reaction can not only provide useful substances for human beings, but also eliminate substances harmful to human beings, which is correct;

C from the perspective of circular economy, waste is a misplaced resource, which is correct.

D, in the production process of "resources-products-wastes", following the law of conservation of quality, D is wrong;

(2) As can be seen from the hydrogen cycle diagram.

A. Light energy is converted into electric energy through chemical reaction, which is correct;

B. In the ideal cycle of hydrogen, chemical changes have taken place, and water is decomposed under the action of light energy to produce hydrogen; B is wrong;

C. the decomposition reaction of water needs to absorb energy and light energy. That's right.

(3) Chemical equation of 2H2O solar energy in water decomposition reaction. Catalyst 2H2 =+O2 =

So the answer is: (1)ABC(2)AC(3)2H2O solar energy. Catalyst 2H2 =+O2 =