"Please pne up when borrowing books" 的英文表达为 "Please queue when borrowing books".
"Queue" 是英语中的一个动词，意思是 "排队"。
例句：
"Please queue up at the counter to borrow your books."
"Customers are asked to queue when returning or borrowing books."
中文翻译：
"请在柜台处排队借书。"
"客户在还书或借书时被要求排队。"