2022英语周报七年级下册新目标答案

31.(12分,除标注外,每空1分)(1)灰色灰色鼠与黑色鼠杂交,后代均为灰色2)不能根据子代的表现型无法判断该性状的遗传与性别是否相关联(3)两F1与隐性纯合的黑色长尾鼠杂交,F2出现四种表现型,并且比例为1:1:1:1,推断出F1产生四种配子,比例是1:1:1:1,说明两对基因位于两对同源染色体上(2分)(4)1/45)灰色短尾雌Ⅹ灰色短尾雄、灰色长尾雌×灰色短尾雄、黑色短尾雌×灰色短尾雄、黑色长尾雌×灰色短尾雄(答出任意两种即可,4分)【解析】(1)(2)略(3)F1与隐性纯合的黑色长尾鼠杂交,F2出现四种表现型,并且比例为1:1:1:1,推断出F1产生四种配子,比例是1:1:1:1,说明两对基因位于两对同源染色体上(4)根据子代表现型灰色短尾鼠的比例为3/16,可得亲代基因型为RrXX× ROXY,(5)遗传性状与性别相关联可以判断基因在性染色体上,可以选择隐雌×显雄或杂雌×显雄进行杂交,若后代表现型与性别相关联则相应基因在X染色体上,若性状与性别无关,则在常染色体上

写作Paragraph lAnd not very long after that, he made a surprising decision. Hedecided to use all hghts to prepare for his li fe at the remoteisland. In the first year he sent troops, veterinarians and animalrainers to kill the wild animals or train them for good use. Thetask was so huge but it was wor thwhile then the king sent a lot offarmers to start a wide rice field and began to grow rice. Next head many facilities, from hospi tal to school, built.【高分句型一】After that he sent a lot of educated people there. At last he sentall his families to the island.(岛屿的建设和发展)Paragraph 2Finally the time came when the king had to be thrown away to thesland.【高分句型二】 Wi th many strong soldiers catching him,hesmiled. He had prepared every thing for the final day.When he was sent to the island, the is land had taken on a new lookEverybody there lived a comfortable life and the king was welcomedwarmly by his people. They cheered, long live the wise kingThe wise king lived happily ever after. The clever people live nown the world to prepare for their life in the future.(国王最终在自己的岛屿上生活)

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