题干

诗句“人生自古谁无死,留取丹心照汗青”是( )写的。

A:李清照

B:鲁迅

C:文天祥

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答案(点此获取答案解析)

C

同类题2

阅读理解

B

    John and Ann are from Dublin, Ireland. They've been friends since they were children. They lived in the same neighborhood when they were young and they went to the same university.

    Today John is a 34-year-old engineer. He works in the heart of Dublin. He is very busy and doesn't have much free time. He found a maid (女佣) to clean his house on Saturdays, but during the week he has to make the bed and tidy up his room. He must also wash the dishes. Sometimes he cooks a meal, but most of the time he stops at a restaurant near his home and buys a meal for dinner. He often arrives home very late. Luckily, his maid is quite professional and takes good care of the house. In just 6 hours, the house begins to shine, with a fresh look and clean air to breathe.

    Ann is 35 years old. She lives in a small village in Dublin. She works as a doctor at the village's health center. She starts working at 9 a.m. and finishes at 4 p.m. There is a half-hour lunch break at 12:30 p.m. After work, Ann has to pick up her two daughters from school. After they arrive home, the children do their homework while Ann prepares dinner. Her husband (丈夫) usually does part of the chores when he gets home. First he prepares the children's bath and then he washes clothes. Before dinner, he hangs up the clothes and then the children help him to lay the table (摆好餐具) and ... it's dinner time! After dinner, Ann's husband usually does the dishes while she tidies up the kitchen. When there is too much rubbish, she takes it out.

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同类题4

野生型果蝇的眼形是圆眼,某遗传学家在研究中偶然发现一只棒眼雄果蝇,他想探究果蝇眼形的遗传特点,便设计了如图甲所示的实验(亲代果蝇均系纯合子).雄果蝇的染色体组成图及性染色体分区段如图乙所示.据图分析回答下列问题:

(1)若F2中圆眼:棒眼=3:1,则该对性状受一对等位基因控制,____ 是显性性状.若F2中圆跟:棒眼=27:37,则该对性状受____ 对等位基因控制.

(2)若该对性状受常染色体上一对等位基因控制,与果蝇眼形相关的基因型有____ 种;若这对基因位于性染色体(X、Y染色体上的I区段),则与果蝇眼形相关的基因型有____ 种.

(3)若F2中圆眼:棒眼=3:1,且仅雄果蝇中有棒眼,则控制圆眼、棒眼的等位基位于性染色体上,可能位于乙图中X、Y染色体的____ 区段.

(4)若已经研究清楚,该对性状受常染色体上一对等位基因控制.圆眼纯合果蝇与棒眼果蝇杂交,在后代群体中出现了一只棒眼果蝇.出现该棒眼果蝇的原因可能是亲本果蝇在产生配子过程中发生了基因突变或染色体片段缺失,为了探究其原因,现有人设计了如下的实验步骤,请您帮助完成结果预测.(注:一对同源染色体都缺失相同片段时胚胎致死;各型配子活力相同)

①用该棒眼果蝇与基因型为Aa的果蝇杂交,获得F1

②F1自由交配,观察、统计F2表现型及比例.

结果预测:

Ⅰ.如果F2表现型及比例为圆眼:棒眼=____ ,则为基因突变;

Ⅱ.如果F2表现型及比例为圆眼:棒眼=____ ,则为染色体片段缺失.