单选题 She is ______ interested in physics. She often works at it until ______ into the night.

【正确答案】 C

【答案解析】[解析] 考查副词用法。deep和deeply都是副词，区别在于前者多用于具体事物，后者多用于抽象事物。从本题来说，“深感兴趣”是抽象的，而“夜深”则是具体的，所以选C。