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【单选题】
地球的保护伞是什么A.
平流层
B.
对流层
C.
臭氧层
D.
中间层
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【简答题】描述Matthew和Franklin所做的证明DNA半保留复制的实验。
【简答题】动词运用。 I'm an American boy. I 1______ (come) to China in 2006. I 2______ (study) here for two years. My father often 3______ (take) me 4______ (play) football on the playground. Last Sunday, I 5______ ...
【简答题】Matthew
【简答题】点估计和区间估计
【单选题】After graduation I hunted for jobs here and there, meeting with many setbacks,_______ I obtained a vacant post in a small business.
A.
though
B.
in that
C.
unless
D.
until
【简答题】什么叫区间估计?什么点估计?置信度与区间估计有什么关系?
【单选题】This is the third time I _______ Beijing. The second time I ______ here was on Christmas Day last year.
A.
have visited; came
B.
have visited; have come
C.
visited; came
D.
visited; have come
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