“鋼铁算是挺坚硬的东西了,但是只要提高溫度,也会熔融成为液体,甚至进而沸騰化汽。天下无难事,只怕心不专。有志者事竟成。貴在坚持,要坚持到最后一秒钟……”这是当我訪問于振善同志的时候,他向我反复申述的几句話。这几句話是他多年来的座右銘,也是他一生向科学进軍的頑强精神的很好概括。于振善同志現在是河北大学数学系的教师。然而,在旧社会,他却是一个只念过三年小学的木匠。他是怎 “Steel is a very hard thing, but as long as the temperature increase, it will melt into a liquid, or even boil off steam. There is no difficulty in the world, I’m afraid I do not have the expertise .Is insisting that you should stick to the end A second ... ”This is a few words he repeated to me when I visited Comrade Zhen Shan. These few words are his motto for many years and a good summary of his tenacious spirit of marching toward science in his life. Comrade Yu Zhen-shan is now a teacher of Mathematics Department of Hebei University. However, in the old society, he was a carpenter who had only attended elementary school for three years. How is he?