The paradox and the difficulty is that you live in a dualistic universe, and virtually any action you take is met by a counter-force.
矛盾和困难的是，你们居住在一个二元的宇宙中，并且实质上你们所采取的任何行动都会遇到一个反作用力。
2
Traceability of airborne particle counter has its own specialty, there is a big difficulty, at home and abroad many people are working to the calibration of airborne particle counter for many years.
尘埃粒子计数器的量值溯源因其特殊性，存在很大难度，多年来国内外都在致力于尘埃粒子计数器的校准研究。
3
In this paper I explain the difficulty that price marketing exists, and analysis the price marketing systematically, and put forward the relevant counter-measure.