It got terribly cold. The cold was ______.

A frightening  B horrifying   C shocking  D frightful 

这是《新概念英语》第二册Lesson 75的练习，答案为什么是D，选项A对不对？

解释：

terribly:

[usu. as submodifier]very; extremely非常，很

I'm terribly sorry. 我非常抱歉。《新牛津英汉双解大词典》

frightfully

[as submodifier](dated) very (used for emphasis)

(旧)很，非常（用于加重语气）

It was frightfully hot. 天气热得要命。

I'm frightfully sorry. 我非常抱歉。《新牛津英汉双解大词典》

frightening 

adj. 吓人的,可怕的

His aspect was frightening. 他那副样子很可怕。《简明英汉词典》

根据上述词典中的解释，terribly 与 frightfully意义相近，所以答案选D。