The optimal combination of benefits and risks is the best combination of benefits and risks. If the benefit is certain, the risk is minimized; According to the travelling expenses data, in mid-december in zhejiang market price of R22 / everything/R410a 1.53/2.57/36500 yuan/ton, respectively, from early September at the bottom of the periodic rebounded 20% / 38% / 46% respectively, the downstream demand off-season, but the price of raw material hydrofluoric acid, chloride methane due to higher environmental factors superposition enterprise starts ascending space limited (according to the travelling expenses, effective device industry starts. Seventy percent), refrigerant price off-season does not light. Moreover, the average price of r22/r22/r134a/R410a has increased by 68%/32%/103%, respectively, from 2016Q4. Compared with the raw material spread, we have been able to calculate the company's overall profitability. In 2018, we need: 1. Principles of securities investment The response to multifactor values is rigid. Rigid instinct (also called the unconditioned reflex) refers to several different tropism in a certain direction organically to form a complete reflex arc reaction mode, it is congenital formation of lower animals, to determine the external stimulation produced by the reaction of the relatively fixed form. Rigid instincts are organisms after a long period of natural selection, gradually formed the low passively adapt to the environment of a kind of way of life, it is born, determined by the genetic factors, to appear without the need for training the day after tomorrow. For example, mechanical stimulation of the coelenterates and arthropods; The newborn's grip reflex, sucking reflex and adult knee jerk reflex, scratching reflex, etc. Instinct is the development form of tropism, rigidity of compound stimuli from a specific things comprehensive response, it makes the organism and the external environment to produce a higher level of coherence, formation of more advanced orderly structure. Anyway, rigid instinct is lower biological things outside of the value of multiple factors is the primary way of ordering reaction, is on the tropism, extension, and the synthesis, make tropism has more purposeful, tropism is get distillation.