The principle of rational investment: investment in securities investment in analysis and comparison. Someone asked: "is value subjective or objective?" In fact, the formulation of this question does not accord with dialectical materialism. Because if that value is an objective rather than subjective, which he said is equal to the value only from the objective existence of its form, without subjective reflection of form and at the same time, the or value of the objective things can't be human understanding, that an agnostic mire; On the contrary, if think value is subjective, not objective, it is said that only a reflection of its subjective value form, rather than the form of the objective and at the same time, the value is entirely subjective since birth, not the reflection of objective things, which in turn into a mire of idealism. Mr Draghi said the positive news about eurozone growth meant that the bank's council was "increasingly confident" that inflation would strengthen over the long term and become "self-sustaining". But he added that the current policy needed to be maintained to "maintain inflation", reaching the ECB's target of close to 2 percentage points. His European central bank held interest rates unchanged and signaled that it would maintain its aggressive currency, despite data showing strong economic performance in the region. Generally speaking, the interest rate varies according to the term of measurement, indicating that the method has annual interest rate, monthly interest rate and daily interest rate.