2 sentences

1. 这首歌在七十年代很流行。

   zhè shǒu gē zài qī​shí​nián​dài hěn liú​xíng.

   This song was popular in the 1970s.

   Source: Tatoeba

2. 他在七十年代曾是一个嬉皮士。

   tā zài qī​shí​nián​dài céng shì yī gè xī​pí​shì.

   He was a hippie in the seventies.

   Source: Dong Chinese Dictionary