英语翻译No one knows for sure when advertising first started.分析句

英语翻译（1）No one knows for sure when advertising first started. No one knows for sure when the first people arrived in ____ no one but" wrong" way corrigan knows for sure翻译 英语 no one knows for sure, and making prediction 英语翻译No one knows when such a custom first ______.A.came into NO one knows for sure,and making predictions is a risky busi But no one knows for sure how much crude oil lies buried ben no one knows for sure what use can be made of the computer i no one really knows exactly when the first people arrived in no one knows when i am not The meeting _______ for five hours.No one knows when it will 英语翻译No one knows who invented the pencils or when it happene