–When has the country been united as one?1998 I suppose.A. InB. FromC. AfterD. Since

问题补充：

–When has the country been united as one?

--1998, I suppose.

A. In

B. From

C. After

D. Since

答案：

A. In

B. From

C. After

(答案→)D. Since

解析：句意，这是两个人之间的对话。第一个人说：“这个国家是什么时候统一的？” 第二个人说：“我推测，是从1998年开始”。表示“从……以来”，故选D。