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问题 单项选择题

植物所需的全部元素均来自土壤，以下都是植物生命活动所需的大量元素的是（）

A.碳；钙；磷；铁 

B.钾；镁；氮；钠 

C.硫；钙；镁；氮 

D.碳；氢；氧铜

答案

参考答案：C

判断题

植物对昼夜温度交替变化的反应称为物候节律.
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问答题

Suppose a foreign friend of yours has written to inquire about the possibility of making a seven-day visit in China. Write a reply to give him some information. The following should be included:
(1) The place you recommend for him to visit and the reasons ;
(2) The suggested route and the timetable of the visit;
(3) Some advice on how he should prepare for the visit;
(4) Your arrangement for his visit to Beijing.
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