问题补充：
Although she felt tired, she didn’t stop working.
A. She felt tired, she didn’t stop working.
B. She felt tired, so she stopped working.
C. But she felt tired, she didn’t stop working.
D. She felt tired, but she didn’t stop working.
答案：
A. She felt tired, she didn’t stop working.
B. She felt tired, so she stopped working.
C. But she felt tired, she didn’t stop working.
(答案→)D. She felt tired, but she didn’t stop working.
解析：句意：尽管她感到很累，但并没有停止工作。although 引导让步状语从句，虽然，尽管，它与but 只能用其中一个，故答案为D。
