词汇	挺起腰杆
释义	挺起腰杆 straighten up
随便看	second order perturbation solution second-order perturbation solution second-order per-turbation solution Second-order perturbation theory second order phase change second-order phase change second-order phase-locked loop second-order phase transformation second order phase transition second-order phase transition second-order pinacoid second-order PLL second order plotting instrument second-order polarizability secondorder polynomial second order polynomial second-order polynomial second-order polynomial curve second-order potential coefficients second-order precision second-order predicate second order predicate calculus second-order predicate calculus second-order predicate logic second-order presure-gradient microphone