By day, Robert Titterton is a lawyer. In his spare time though he goeson stage beside pianist Maria Raspopova—not as a musician but as her pageturner. “I’m not a trained musician, but I’ve learnt to read music so I canhelp Mariain in her performance.”
上面一段摘自2021年新高考考试英语全国卷I的阅读理解B。请问第一句开头的 by day 是什么使用方法？这个 by day 可以换成 in the day,during the day 吗？
你的句子中的 by day 完全可以换成 in the day或 during the day，也可以换成 in the daytime，它们之间的细微不同是：by day 除表示“在白天”外，有时隐含有“趁着白天”的意思（与 by night 相对）。如：
Cats sleep by day and hunt bynight. 猫白天睡觉，夜里捉老鼠。
假如不考虑这种隐含意思，它们的使用方法基本是相同的。
