He is an expert in sales and marketing.for the last three years,mr wang has worked for JHS company.

请帮忙翻译：He is an expert in sign language. 英语翻译he is an expert is in reserve and resource definition and classification,the U.S.Securities and Exchange Commission (SEC) disclosure requirements,and professional ethics and practices. He considers himself an expert on the subject,in fact,he is poor on it.怎么译 sales.he is an expert and maketing英文翻译 He is an expert in sales and marketing.for the last three years,mr wang has worked for JHS company. 英语翻译By the time that a student reaches his senior year in high school ,he is likely to believe that he is an expert in reading. an expert on和be expert in的区别 he considers himself an expert on the subject 我认为是 he considers himself is an expert on the subject 我是按照中文翻译的就是这样?语法新手. 麻烦看下这三个句子有没有语法错误Can I put you forward to club secretary?Linda is an agricultural expert.Linda is an expert in agriculture. On stage right near the dressing rooms,Keith Collea,an American 3D expert,sits in the dark watching his screens.“China is where it’s at,” he says.请问China is where it’s at,怎么翻译?你是怎么理解这句话的意思? Dame Daphne Sheldrick is an elephant expert (专家).She works with elephants in Kenya,Africa (非洲 英语翻译By the time that a student reaches his senior year in high school,he is likely to believe that he is an expert in reading.No matter how good he is,he can still improve.How do you read an article in a textbook?Do you have a certain idea of my father is an engineer .what's your father?He ______ as an architect in shenzhen. 是be an expert in/at/on ,还是be expert in/at/on? an expert in/at/on/with有什么区别?例子：1.an expert in/at teaching small children意思就是说an expert in和an expert at通用对吗?2.an expert in economics3.an expert on foreign affairs4.an expert with the needles an expert in/on/at有什么区别 a specialist or an expert in genetics（a noun） |英语|(在...方面)何时用IN何时用AT?He is an expert at troubleshooting.他是位排解争端的能手.He is lacking in courage.他缺乏勇气.请问什麽时候用in什麽时候用at?请再举些例子.