【B18】
A. a certain
B. certain
C. certainty
D. certainly
The underlined phrase "adopted children" in Paragraph 2 means ______.
A. children born in the family
B. children who left the family
C. children taken legally into a family they were not born into
D. children who are unable to take care of themselves
We don't realize that our eyes are important until ______.
A. we are sick
B. we can't see clearly
C. we wear glasses
D. we burst into tears
【B20】
A. on
B. to
C. in
D. up
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