问题 选择题

下图表示基因型为AaBbDd的某动物正在分裂的细胞,叙述正确的是

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A.该状态的细胞可能发生基因重组现象

B.若①上有A基因,④上有a基因,则该细胞一定发生基因突变

C.①②③可组成一个染色体组,④⑤⑥为另一个染色体组

D.若①是X染色体,④是Y染色体,其余则是常染色体

答案

答案:C

问答题
单项选择题

I was a single parent of four small children, working at a low paid job. Money was always tight, but we had a (1) over our heads, food on the table, clothes on our backs, and if not a lot, always (2) . Not knowing we were poor, my kids just thought I was (3) . I’ve always been glad about that.

It was Christmas time, and although there wasn’t (4) for a lot of gifts, we planned to celebrate with a family party. But the big (5) for the kids was the fun of Christmas (6) .

They planned weeks ahead of time, asking (7) what they wanted for Christmas. Fortunately, I had saved MYM120 for (8) to share by all five of us.

The big (9) arrived. I gave each kid a twenty-dollar bill and (10) them to look for gifts of about four dollars each. Then everyone scattered. We had two hours to shop; then we would (11) back at the "Santa’s Workshop"

Driving home, everyone was in high Christmas spirits, (12) my younger daughter, Ginger, who was unusually (13) She had only one small, flat bag with a few candies—fiftycent candies I was so angry, but I didn’t say anything (14) we got home. I called her into my bedroom and closed the door, (15) to be angry again. This is what she told me.

"I was looking (16) thinking of what to buy, and I (17) to read the little cards on the ’Giving Trees’. One was for a little girl, four years old, and all she (18) for Christmas was a doll. So I took the card off the tree and (19) the doll for her. We have so much and she doesn’t have anything. "

I never felt so (20) as I did that day.

6()。

A.little 

B.less 

C.enough 

D.more