1.public speaker 公共演說(shuō)家；發(fā)言人

例句：Faith in yourself, your topic, and your general sanity is a must if you are to be a better public speaker.
要對(duì)你自己和你的主題有信心。 如果你要做一個(gè)更好的公眾演講者你必須保持清醒的頭腦。

2.conducted 從事；引導(dǎo)；負(fù)責(zé)；管理

例句：You must choose what best suits the operation being conducted.
您必須選擇好什么時(shí)候最適合進(jìn)行操作。
3.toxic substances 有害物質(zhì)；有毒物質(zhì)

例句：Avoid placing water containers in areas where toxic substances, such as gasoline and pesticides, are present.
避免將食水的容器存放在靠近有毒物質(zhì)的區(qū)域內(nèi)，如汽油和殺蟲劑。

4.clean up 清除；打掃；收拾干凈

例句：Under pressure from the public, many regional governments cleaned up their beaches.
迫于公眾的壓力，許多地區(qū)政府治理了海灘污染。