Doctors couldn’t say what was wrong ________ they didn’t know what kind of snake it was．

1. A.
   so
2. B.
   because
3. C.
   or
4. D.
   but

根据短文内容回答问题.
If a snake bites you, take a photo with your mobile phone! It may save your life. This is the surprising advice of a British cook.
One day Henry Jackson was working in a restaurant kitchen. He picked up a dish from the table, and suddenly a snake appeared…and bit him on the hand.
“I went to try to pick it up and it bit me again. I threw it across the kitchen, and it landed in the fridge. So I closed the door,” Mr. Jackson said.
Anyway, Mr. Jackson stayed cool and he took a photo of the snake with his mobile phone. Soon his hand began to ache and he went to hospital. Then his chest began to hurt. Doctors couldn’t say what was wrong because they didn’t know what kind of snake it was. Then Mr. Jackson remembered his mobile phone photo. The doctors sent it to London Zoo. When they knew the kind of snake, they could give Mr. Jackson the right medicine, and he left hospital the next day.
【小题1】What did Mr. Jackson do after the snake bit him again?
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【小题2】Why did Mr. Jackson close the fridge door?
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【小题3】What did Mr. Jackson feel after taking a photo of the snake with his mobile phone?
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【小题4】Why couldn’t the doctors help Mr. Jackson at first?
【小题5】What can you learn form the story?
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