mid 20th century meaning in English

二十世纪中叶

The sandy dust disasters during the early and mid 20th century in canada and former ussr
20世纪中前期加拿大及前苏联的沙尘灾害
Quarrying started in early 19th century to mid 20th century , mainly at the north coast of the island
石矿业主要集中在岛的北岸，由十九世纪初开始，到二十世纪中结束。
In mid 20th century , with the growth of science and technology , human ' s development and utilization of sea resources have become possible
海洋蕴藏着巨大的宝藏。二十世纪中期，随着科学技术的发展，人类开发利用海洋资源成为可能。
Huang yao 1917 - 1987 pioneering his work in creative calligraphy in the mid 20th century , was mentioned by art historian wang nanming that his calligraphy painting predates modern calligraphy in mainland china
黄尧1917 - 1987在20世纪中期里开拓了其书法创造的工作,被艺术历史学家王南溟提到他的书法在中国为前卫书法。
Explain that man has entered the space age since the mid 20th century . not only were more planets , asteroids and satellites discovered , but also scientists were able to obtain the information of their surface structures by various means
说明在二十世纪中期以后，人类进入太空时代，除了发现更多行星小行星和星外，科学家并利用种种不同方法，取得这些星体表面结构的资料。