问题补充:
I toured Zhangjiajie, I was deeply impressed with its beautiful scenery.
A. For the first time
B. At first
C. It was the first time
D. The first time
答案:
A. For the first time
B. At first
C. It was the first time
(答案→)D. The first time
解析:逗号前后都是一个句子,所以整个句子缺少连词,只有The first time是连词,引导的是时间状语从句,故选D。