问题补充：
She was afraid the dog in case it became dangerous .
A. of exciting
B. to excite
C. that she excited
D. to be exciting
答案：
A. of exciting
(答案→)B. to excite
C. that she excited
D. to be exciting
解析：be afraid后面既可以跟不定式be afraid to sth又可以跟动名词be afraid of doing sth , 但前者的意思是：害怕/不敢做某事；后者的意思为：对可能出现的结果的发愁或忧虑，试比较以下两个句子：She was afraid to wake up her husband . ( perhaps because she feared that he would be annoyed or angry ) 她不敢唤醒她的丈夫。（可能因为她害怕他会不高兴或生气）
She was afraid of waking up her husband . ( perhaps because he was ill , or in need of extra sleep )她担心吵醒了她的丈夫。（可能因为他生病了或需要一些额外的睡眠）
