Abstract: The reason that the productivity and reserves of natural gas fall behind may not be attributed to "more stress on oil than gas" in our work,rather. It is important to encourage the policy of energy resources with emphasis on exploration; and to establish "four new concepts" (new way of thinking, new area, new realm and new depth) which is based on new way of thinking; and above all, it is critical to carefully select areas as regards to the generation and preservation of hydrocarbons. Nearly 20 years, the fact that "theory always lagged behind practice" is due to the continuous confinement of thinking by traditional geoscience concepts as fixistic ideas, pre-war geological knowladge during major oil/gas findings. Taking Tarim and East China Sea as examples, the discussion is centered on whether the two basins are intracratonic basins or remanent back arc basins. The author advocates the concept of back arc basins, and suggests they are most important selected areas in China for the exploration of giant gas fields at the present.