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【简答题】
是指从左到右与从右到都一样的正整数．如22，，11，3443，94249等．显然2位有9个：11，22，33…，99.3位有90个：101，111，121，…，191，202，…，999．则： （1）4位有（ ）个； （2）2n+1（n∈N+）位有（ ）个。
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举一反三
【单选题】When a student said in class, "I comed home at 6 o'clock yesterday", the teacher said "Came not comed”. Which rule of effective feedback does the teacher NOT obey?
A.
Relevance.
B.
Accuracy.
C.
Guidance.
D.
Timelines.
【简答题】The teacher said,"The sun rises in the east and goes down in the west." The teacher said that the sun in the east and down in the west.
【简答题】The teacher said "You are what you eat" to show the importance of eating ___________to stay healthy.
【单选题】The teacher said,"The sun rises in the east." The teacher said that the sun ______ in the east.
A.
rose
B.
risen
C.
would rise
D.
rises
【简答题】A. The teacher said, "That student is lazy." B. "The teacher", said that sudent, "is lazy." Question: Who was lazy?
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