单选题 Speaker A: Could I trouble you to return these two books for me?
Speaker B: ______
A. It's no trouble at all.
B. Yes, please.
C. Why didn't you go to the library yourself?
D. Sure, I'll be glad to.

【正确答案】 D
【答案解析】[解析] A方请求B方帮忙还书，B方应做出同意或拒绝这一请求的反应。选项D“当然，我很乐意”是这一对话情景下的恰当反应。C项显得不太礼貌，而且句中的时态也不正确。