It is only through struggle and hard work,and over a long period too,that we can eliminate the old evils,the old filth,and prevent setbacks or even reversals in the revolution.

• 旧毒，污浊，革命进程中的某些波折，以及可能的回头路，只有斗争和努力才能够克服，而且需要长期的斗争和努力。