钙是人体必需的元素，缺钙会造成骨骼和牙齿脆弱。当从食物中不足以得到人体所需的钙时，就

集中基坑积水排出围堰外的泵站中，水泵应选用______。

A．大容量中高水头水泵
B．小容量中高水头水泵
C．小容量中低水头水泵
D．大容量中低水头水泵

阅读理解。

                Yellow Dress

                              By Janet Lee

          Mary had a yellow dress 

       Bought from the department store.

        It looked as beautiful as the moon,

             And as bright as the sun.

              Mary wore all the time

                 The yellow dress

                  I felt so right.

            Every day from day to night

            I saw her in the dress so bright.

             "Buy me a yellow dress,"

              I cried to Mom and Dad,

               "As beautiful and bright

            As the dress the girl living near has!"

               I cried and cried and cried,

               Until they said with sad eyes, 

            "We need food for your baby sister,

           And clothes for your coming brother."

                  Since then I've learned 

          Mary's yellow dress Is better to dream of

                    Than to ask for.

1. Why does the writer say, "Every day from day to night / I saw her in the dress so bright"?

A. The writer lived with Mary.

B. The dress had sun shapes on it.

C. The writer liked the dress very much.

D. The dress was Mary's school uniform.

2. What did the writer's parents mean by their words?

A. They did not like the yellow dress.

B. They did not have money for a dress.

C. They already had a dress for her baby sister.

D. They would ask Mary where to buy the yellow dress.

引起出血性疾病较常见的因素是（）。

A.血管外因素

B.凝血因子缺乏

C.肝素或香豆类药物

D.抗凝血物质活性增加

E.血小板异常

人体维持内环境的相对稳定，对于细胞正常生命活动非常重要。请回答下列问题。

体液中的水和电解质的含量也是相对稳定的。如果脑中缺血，使细胞内Na⁺浓度升高，会引起细胞（），如果人体大量失水，血浆渗透压将（）引起（）激素分泌增加，（）中枢兴奋。

日产NISSAN总部位于日本什么地方？