免疫组化过程中，阻断内源性过氧化物酶活性步骤是在（） A.一抗反应后 B.一抗反

阅读下面的材料，然后根据材料回答问题。

     Elizabeth lived with her six children in a small house. One winter, there was a big flood (洪水), and quite

a few houses were washed away, but Elizabeth's house was high enough to escape it.

     Elizabeth helped one of the families which had lost everything. She shared her home until the family could

build a new house. Elizabeth's friends could not understand her since she already had so many children to take

care.

     "Well," Elizabeth explained to her friends, at the end of World War II, there was a poor woman in a town

in England. Her husband had been killed in the war and she had a lot of children, just like me now. The day

before Christmas, this woman said to her children, "We won't be able to have much for Christmas. I'm going

to get just one present for us all.Now I'll go and get it. She came back with a little girl who had no parents.

Here's our present, she said to her own children. The children were more than excited to get such a present.

They welcomed the little girl warmly, and she grew up as their sister. I was that Christmas present."

1. How many children did Elizabeth have?

    ____________________________________________________________

2. What did Elizabeth do after the flood?

    ____________________________________________________________

3. The Christmas present was Elizabeth herself, wasn't it? 

    ____________________________________________________________

4. What do you learn from the story?

    ____________________________________________________________

已知y=log_a（3-ax）在[0，2]上是x的减函数，则实数a的取值范围为______．

某会计账户的期初借方余额为，5000元，本期贷方发生额为12000元。期末借方余额为840Q元，则本期借方发生额为( )。

A．8600元

B．15400元

C．1400元

D．14500元

电能计量装置投运前，进行验收核查、试验的内容有哪些？

荧光原位杂交(fluorescence in situ hybridization)