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---How long have you known the doctor ?  ---_________he helped me three years ago.
#56019
A
When　
B
Before　
C
Because
D
Since
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How are you now? Go to see the doctor ____ you don’t feel well.
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Jack usually goes to school by bike, ________ today he walked to school.
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 — Can you tell me ______ it is from here to the Summer Palace?— Let me see. It's about 15 minutes' ride.
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You shouldn’t keep a pet _______________ you have enough time to care for it.
#56035
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if
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unless
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