1 sentence

1. 历史学家正在深入研究苏俄时期的社会制度。

   lì​shǐ​xué​jiā zhèng​zài shēn​rù yán​jiū Sū'é shí​qī de shè​huì zhì​dù.

   Historians are conducting in-depth research into the social system of the Soviet Russia period.

   Source: Dong Chinese Dictionary