题目内容：
根据下面资料，回答题 Over the summer， my family took a trip to Iceland to see the natural beauty of it．Little did I 21 I would wake up one morning to have my eyes swelled up( 肿 胀 )like balloons! I was frightened．So many questions were 22 through my head．
Am I allergic(过敏的)to something? Was there some Icelandic disease that I 23 ?The only help I received was some allergy medicine 24 a clinic nearby．Nothing was working．
When the trip was over,I went to see my doctor．She gave me eye drops, but clearly they weren't worth the time or 25 and the swelling got worse and worse．
I finally decided that it would be best for me to 26 being so sad and take it easy and have fun．
It was summer after all.I had a fun night with my friends as if nothing was 27 .The next morning I woke up and went to 28 how swollen my eyes
were,only to find myself 29 at my normal face．
It was a miracle(奇迹).I 30 asking myself why I hadn't done that earlier．
Was being with my friends and having fun really the 31 to my problem?
To this day I still do not know what I had,and 32 do any of the many doctors that I 33 during the summer．
I would really like to go back to Iceland to see the Northern Lights, 34 I am very much frightened that I am just allergic to the country．I hope I never 35 having such terrible swelling in my eyes ever again．
第（21）题选 A．know
A．know
B．doubt
B．doubt
C．insist
C．insist
D．fear
D．fear
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答案解析：