在英语中，如果您想表达“打车时听到昆曲”，可以这样说：
- “I heard Kunqu opera while taking a taxi.”
- “While riding in a taxi, I was serenaded by Kunqu music.”
- “In the taxi, I unexpectedly tuned into a performance of Kunqu.”
- “Taking a taxi, I was surprised to hear Kunqu being played.”
这些表达方式都能清晰地传达出您在乘坐出租车时意外听到了昆曲这一情境。