血清清蛋白（pI为4.7）在下列哪种pH值时带正电荷（） A.pH4.0 B.pH5
题型：单项选择题
问题：
血清清蛋白（pI为4.7）在下列哪种pH值时带正电荷（）
A.pH4.0
B.pH5.0
C.pH6.0
D.pH7.0
E.pH8.0
题型：单项选择题
根据短文内容及首字母提示，在下文空格处填入适当的词使短文完整，每空一词。
March 5th is “Lei Feng Day”. It started fifty years ago. Now half a
c 1 has passed. Is the spirit of Lei Feng outdated(过时的)?
Some people have shown us that it’s not. But people have a 2
changed the ways to help others.
Zhao Juan has been a volunteer for 15 years. She still remembers her e 3 at a nursing home several years ago. An old man held her hand and said: “You don’t need to do anything for us. Seeing young people here is all we need.”
Those words made Zhao Juan think: in what w 4 can we help people better? “Every person does something to give out positive energy(正能量). And before we give a helping hand, we should find out what they r 5 want,” Zhao Juan said to the Qilu Evening News.
As well as Zhao Juan, other people have shown their understanding of the spirit of Lei Feng.
This past January, a story called “noodle fever” shocked Zhengzhou, Henan. One kind man, Li Gang, 42, said in his story that he had a s 6 illness and needed a lot of money for an operation. H 7 ,what he asked for wasn’t charity, but for more people to come to eat noodles at his restaurant.
Li Gang’s story spread q 8 . Soon his restaurant was filled with customers every day and he was a 9 to have his operation on Feb. 2nd this year.
I 10 this way, people could help Li Gang without hurting his dignity(自尊).