When you get on stage for the first time you may be surprised by bright the lights are.A.

问题补充：

When you get on stage for the first time, you may be surprised by bright the lights are.

A. what

B. so

C. how

D. too

答案：

A. what

B. so

(答案→)C. how

D. too

解析：考察从句连词用法。根据句子结构可知，此处为宾语从句，从句中提前bright，用how修饰。

句意为当你第一次登上舞台的时候，你可能会对灯光多么亮而感到惊讶。