黑白电视在50年代开始普及。

Black and white TVs became common in the ___50s.

他50多岁决定开始学习弹钢琴。

He decided to start learning piano in his ___50s.

今天气温会在50多华氏度，记得带件外套。

The temperature will be in the ___50s today, so remember to bring a jacket.