背更多的英语单词用英语怎么说

“Learn more English words” 用英文表达为 "expand one's vocabulary"。
"Vocabulary" 来源于拉丁文 "vocabularium"，意思是 "词汇表"。
例句1:
"I want to expand my vocabulary by reading more books in English." (我想通过阅读更多的英文书来扩大我的词汇量)
例句2:
"Expanding your vocabulary is an important part of learning a new language." (扩大词汇量是学习一种新语言的重要部分)