I like getting up very early in summer.The morning air is so good .A. to be breathingB. to

问题补充：

I like getting up very early in summer.The morning air is so good .

A. to be breathing

B. to breathe

C. breathing

D. being breathed

答案：

A. to be breathing

(答案→)B. to breathe

C. breathing

D. being breathed

解析：考查不定式用法。当不定式前面的形容词是对句子的主语的特点进行补充说明的时候，使用不定式的主动形式表示被动含义。如The book is easy to read。这本书很容易读。本句句意：我喜欢在夏天早起，早晨的空气很好呼吸。本句中的good是对句子主语the morning air的特点进行的说明。故B正确。