题干
选择合适的句子补全对话。
Amy: Where is my ruler, John?
John:____
Amy: No, it's not in my pencil box.
John:____
Amy: Yes, thanks.
A. Look, it's on your desk. B. Is it in your pencil box?
答案(点此获取答案解析）
B,A
2AB(g)，达到平衡的标志是