问题 选择题

一对双眼皮的夫妇,生了一个单眼皮的女孩,如果他们再生一个孩子,是单眼皮男孩的可能性为(  )

A.100%

B.50%

C.25%

D.12.5%

答案

答案:D

题目分析:在一对相对性状的遗传过程中,子代个体中出现了亲代没有的性状,新出现的性状一定是隐性性状,由一对隐性基因控制,亲代的性状是显性性状,亲代的基因组成是杂合的.因此一对双眼皮的夫妇,生了一个单眼皮的女孩,表明单眼皮是隐性性状,双眼皮是显性性状.如果决定双眼皮的基因是显性基因(A),决定单眼皮的基因是隐性基因(a).遗传图解如图:

传图解看出,一对双眼皮的夫妇,生了一个单眼皮的女孩,如果他们再生一个孩子,是单眼皮的可能性为25%.这个孩子是男孩还是女孩的几率各占50%,因此如果他们再生一个孩子,是单眼皮男孩的可能性为25%×50%=12.5%.

故选:D.

阅读理解

India was once part of the British Empire, but thanks to modern technology and a booming economy, it has turned the tables on its former colonial master. Indian tutors are helping to teach math to British children over high-speed Internet connections. Early results suggest the idea is improving exam results. But not everyone is happy at this “outsourcing” of tutoring.

It’s 3:30, and pupils at Raynham Primary School in London are gathering for their after-school maths lessons.

Five time zones— thousands of kilometers away—their math tutors are also arriving for class. High-speed Internet has made it possible for Indian tutors to teach British pupils in real time. Each pupil gets a dedicated one-to-one online tutor. The students work with activities on their computer screen and wear a headset and microphone to talk to their tutor.

The class teacher, Altus Basson, says he has seen an improvement in results. “There are some children who’ve really rocketed in their results. Children who struggleto focus in class focus a lot better on the laptops. The real advantage is that each child gets a focused activity and a single tutor,” he said.

Such individualized teaching is the core idea of Brightspark Education, the company that provides the online tutoring, says founder Tom Hooper. “Children today feel very confident online; they feel very engaged; they feel very in control. And that's half the battle with education.Give them control, make them feel confident and enjoy their learning and you'll see them start to improve and embrace it," he said.

Raynham Primary School is among the first in Europe to try online tutoring. At between $20 and $25 an hour, it's about half the cost of face-to-face coaching. But some people say an Internet connection is not enough of a connection for teaching and learning. Kevin Courtney is deputy General Secretary of Britain's National Union of Teachers. "We think, there's a really important emotional connection between a teacher and a child whether it's a whole class or whether it's one-to-one. You need that immediacy of feedback and we're not convinced that that can happen across an Internet connection. In one of the wealthiest.countries in the world, we think that we can afford to have teachers with genuine emotional connection there with the children," he said.

Brightspark Education says the online tutoring is used only as an addition to supplement regular teaching. The company says its service does not represent a threat to teachers' jobs in Britain.

Parents say they're very satisfied with the results they've seen. And what about the children?Children: "I love it!"I love it!"I hate maths!" So math--or, as the British call it, maths—is still not everyone's favorite subject even with the latest technology to teach it.

小题1:What do we know about the online tutoring?

A.Indian tutors are helping to teach math in Britain.

B.Tutors and students are in different places.

C.An online tutor helps several students at the same time.

D.Tutors and students communicate by telephone.小题2:What can we learn about Brightspark Education? 

A.It shows a threat to teachers’ jobs in Britain.

B.It can take place of the regular teaching.

C.It only pays attention to math teaching.

D.It emphasizes the individualized teaching.小题3:According to Kevin Courtne, _________.      .

A.online tutoring will represent a threat to teachers’ jobs in Britain

B.online tutoring has a great influence on British.

C.the emotional connection between a teacher and a child is important

D.immediacy of feedback can happen across an Internet connection小题4:What’s the best title for this passage ?

A.A New Teaching Pattern

B.Indian Teachers and British Students

C.To Learn Maths with the Latest Technology

D.Indian Tutors Teach British Kids Online

单项选择题