Our school building is old, so we better take good care of it.
My school is quite old. We need to be careful how we treat this old building.
ーOur school building is old, so we better take good care of it.
「私たちの学校は古いので、大切にしないと」
to take good care of ... で「大事にする・大切にする」
ーMy school is quite old. We need to be careful how we treat this old building.
「私の学校はとても古いです。私たちはこの古い建物を大切にしないと」
to treat で「扱う」
ご参考まで！
カナダ 
