One reason is that that there was no Internet or mobile technology in the 1930s.

原因之一是在20世纪30年代还没有互联网和移动通信技术。

youdao

One reason is that that there was no Internet or mobile technology in the 1930s.

原因之一是在20世纪30年代还没有互联网和移动通信技术。

youdao