基因突变、基因重组和染色体变异三者的共同点是（） A.都能产生新基因 B.都在光学显
题型：单项选择题
问题：
基因突变、基因重组和染色体变异三者的共同点是（）
A.都能产生新基因
B.都在光学显微镜下可见
C.都对生物生存不利
D.都对生物进化有利
题型：单项选择题
People say that a mother’s love knows no boundaries (边界). This is true when it comes to my mother. She has given up many things so that my sisters and I could live a better life.
My mother comes from a large family and her parents died when she was quite young. She dropped out of school when she was fifteen because no one could afford to pay her studies. At the age of 19, she married my father and when they had my sisters and I, they moved to the United States so that we could have a better life. My parents did not know English but somehow they communicated with other people. My mother stayed at home and raised us while my father was working. There were so many dangerous incidents that happened where we lived that my mother finally decided that we all moved to Texas when I was seven.
My mother has worked so hard to give us everything. She always tells us that all she wants is for us to be happy.
As the saying goes, “You don’t appreciate (意识到) something until it’s gone.” Well, I finally had a chance to experience it. My mother went to Mexico this winter because she needed to have an operation. It was the first time in my life that my mother was not ther
e to hold and comfort me. Those two weeks when she was away made me realize how much I love her. All she has done for me is incredible (难以置信的). When I suffer she suffers with me. I have to show her how much I care about her. She means the world to me.
小题1:Which is the RIGHT order of the following events?
a. My mother married my father.
b. My mother went to Mexico to have an operation.
c. We all moved to Texas.
d. My mother dropped out of school.
e. They moved to the United States.
f. My mother’s parents died 
when she was young.
A．a, b, f, c, d, e
B．d, e, a, c, f, b
C．f, d, a, b, e, c
D．f, d, a, e, c, b小题2:What does the underlined word “it” refer to in the fourth paragraph?
A．My mother’s experience.
B．My mother’s care for me.
C．The meaning of the saying.
D．My mother’s love.小题3:The writer didn’t realize that he loves his mother very much until ______.
A．they moved to Texas
B．his mother told them all she wanted was for them to be happy
C．his mother left home for an operation
D．his mother died小题4:According to the passage, we can infer that the writer writes the passage in a(n) ______ mood.
A．affectionate (挚爱的)
B．humorous
C．serious
D．bitter
G
G