题干

My friend sends me a ____ (卡片)for my birthday.
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card

同类题1

根据短文内容,从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

    Maybe you are an ordinary student. ____ This is not necessarily so. Anyone can become a better student if he or she wants to. Here's how:

    Plan your time carefully. When planning your work, you should make a list of things that you have to do. After making this list, you should make a schedule of your time. First arrange your time for eating, sleeping, dressing, etc, then decide a good, regular time for studying. ____ A weekly schedule may not solve all your problems, but it will force you realize what is happening to your time.

    Make good use of your time in class. ____ Listening carefully in class means less work later. Taking notes will help you remember what the teacher says.

    Study regularly. When you get home from school, go over your notes, review the important points that your teacher is going to discuss the next day, read that material. ____ If you do these things regularly, the material will become more meaningful, and you will remember it longer.

    Develop a good attitude towards tests. The purpose of a test is to show what you have learned about a subject. The world won't end if you don't pass a test, so don't be over worried.

    ____ You will probably discover many others after you have tried these.

A. This will help you understand the next class.

B. You probably think you will never be a top student.

C. Don't forget to set aside enough time for entertainment.

D. No one can become a top student unless he or she works hard.

E. There are other methods that might help you with your study.

F. Take advantage of class time to listen to everything the teacher says.

G. Make full use of spare time to take note of what the teacher says in class.

同类题5

阅读理解

    Can people change their skin color without suffering like pop king Michael Jackson? Perhaps yes. Scientists have found the gene that determines skin color.

    The gene comes in two versions, one of which is found in 99 percent of Europeans. The other is found in 93 to 100 percent of Africans, researchers at Pennsylvania State University report in the latest issue of Science.

    Scientists have changed the color of a dark-striped zebra-fish(斑马鱼) to uniform gold by inserting a version of the pigment (色素) gene into a young fish. As with humans, zebra-fish skin color is determined by pigment cells, which contain melanin (黑色素). The number, size and darkness of melanin per pigment cell determine skin color.

    It appears that, like the golden zebra-fish, light-skinned Europeans also have a mutation (变异) in the gene for melanin production. This results in less pigmented skin.

    However, Keith Cheng, leader of the research team, points out that the mutation is different in human and zebra-fish genes.

    Humans acquired dark skin in Africa about 1.5 million years ago to protect bodies from ultra-violet rays of the sun (太阳光紫外线), which can cause skin cancer.

    But when modern humans leave Africa to live in northern latitudes, they need more sunlight on their skin to produce vitamin D. So the related gene changes, according to Cheng.

    Asians have the same version of the gene as Africans, so they probably acquired their light skin through the action of some other gene that affects skin color, said Cheng.

    The new discovery could lead to medical treatments for skin cancer. It also could lead to research into ways to change skin color without damaging it like chemical treatment did on Michael Jackson.