Once considered sacred, the deer are now classified as a national treasure, so are protected by law.
訳すと「かつては神聖とみなされ、現在では鹿は国宝と分類されるので、法律によって保護されている。」です。Once considered sacredの部分は分詞構文になってます。この文も比較的平易ですね。では次の文へ。
Last year, the authorities said the deer were causing about 6bn yen ($54m; £41m) in damage to regional agriculture annually, so they would start taking action.
"Nara has a long history of people living side by side with deer in harmony. We want to continue efforts to coexist in peace while preventing damage to crops." one local government official told the Asahi Shinbun.
Bolt has confirmed he will run the 100m and 4x100mrelay at the World Championships in London in August, his final event before retiring.
訳すと「ボルトは8月のロンドンでの世界陸上、すなわち引退前の彼の最後の大会で100mと4×100mリレーに出る事を明らかにした」です。his final eventはthe World Championships in London in Augustの言い換えになってますね。この文章で訳し難いのはconfirmです。基本的には「~を確認する」がconfirmの意味ですが、ボルトがcomfirmした内容は明らかに自分自身の事なので私は「明らかにした」と訳しました。「~と言い切った」と言うニュアンスが最もぴったりだと思います。では最後の文を。
In his final race before London 2017, which takes place from 4-13 August, Bolt showed signs he could well bow out with yet another gold medal.