The prison walls are very high.

监狱的围墙很高。

youdao

The next day in the yard, Tweener sits against one of the massive prison walls.

第二天，在院子里，Tweener坐在地上背靠一段宏伟的监狱围墙。

youdao

Outside the prison walls, rehabilitation and job programmes remain inadequate.

大牢之外，罪犯改造和职业培训工程仍然不足。

youdao

Having served a little time, I can tell you that I saw little effort to put inmates to work outside of the prison walls.

FORBES: Prison Labor Helping to Balance Budgets

Former South African President and anti-apartheid fighter Nelson Mandela, who spent 27 years in jail, once said that in the company of Chinua Achebe's novels "prison walls fell down".

BBC: Chinua Achebe: Obituary of Nigeria's renowned author

The former South African president and anti-apartheid fighter, who spent 27 years in jail, "referred to Prof Achebe as a writer 'in whose company the prison walls fell down'", the statement said.

BBC: Nigerian author Chinua Achebe dies