英语周报2021-2022八新目标22答案

18.ABC【解析】甲基化不影响基因的碱基序列;雄配子中印记重建去甲基化,而雌配子则甲基化,亲代雌鼠的基因A未甲基化,故来自其父方;据图可知,亲代雌、雄鼠的基因型均为Aa,但雄鼠的基因A由于甲基化而不能表达,故雌、雄鼠的表型不同;雌、雄鼠杂交,若以“”表示甲基化,则后代的基因型为AA:AaA'a:aa'=1:1:1:1,即生长正常鼠:生长缺陷鼠=1:1

第三节One possible versionParagraph 1Then one day when we got to the school with his usualbig smile, he started to lean towards me. But I put my handup and said, No, Dad. It was the first time I had evertalked to him that way and he had this surprised look onhis face. I said, 'Dad, I am too old for a goodbye kiss. Iam too old for any kind of kiss, My dad looked at me forthe longest time, and his eyes started to lear. I had neverseen him cry. He turned. ' You are right, ' he said."Youare a big boy .. a man. I will not kiss you anymoreParagraph 2Tears began to well up in franks eyes, as he spokeIt wasnt long after that when my dad went to sea andnever came back. I looked at Frank and saw that tearswere running down his cheeks. Frank spoke again."Guysyou dont know what I would give to have my dad give mejust one more kiss on the cheek

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