It was nine years ago when I came to China for the first time I began to learn Chinese.

问题补充：

It was nine years ago, when I came to China for the first time I began to learn Chinese.

A. where

B. how

C. that

D. which

答案：

A. where

B. how

(答案→)C. that

D. which

解析：句意：就是在九年前当时我第一次来中国我开始学习汉语的。这里用的是强调句，强调结构是：It is/was+强调部分+that…，判断是否是强调句的方法是：去掉强调结构，如果这句话仍然成立，就是强调句，这句话如果去掉强调结构是： I began to learn Chinese nine years ago, when I came to China for the first time所以是强调句，所以选C。