单选题 During the dinner we had (agreeable conversation)--(nothing extraordinary)--but (catching up) on recent events of (each other's life).

【正确答案】 C

【答案解析】在介词but之后，如果其前有动词do的某种形式，其后不定式一般不带to，反之则必须带to，表示“不得不，只能”。所以应将catching up改为to catch up。