题干

如图是由六个完全相同的正方体堆成的物体,则这一物体的正视图是(   )
 

A:

B:

C:

D:

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答案(点此获取答案解析)

A

同类题1

阅读下列短文,从每题所给的四个选项(A、B、C和D)中,选出最佳选项。

B

    Our risk of cancer rises as we age. So it makes sense that the elderly should be routinely screened for new tumors(肿瘤)—or doesn't it?

    While such careful tracking of cancer is a good thing in general, researchers are increasingly questioning whether all of this testing is necessary for the elderly. With the percentage of people over age 65 expected to nearly double by 2050, it's important to consider the health benefits of screening and the costs of routine testing.

    In many cases, screening can lead to additional operations to remove cancer, which can cause side effects, while the cancers themselves may be slow-growing and may not cause serious health problems in patients' remaining years. But the message that everyone must screen for cancer has become so ingrained that when health care experts recommended that women under 50 and over 74 stop screening for breast cancer, it caused a strong reaction among doctors, patients and advocacy(拥护) groups.

    It's hard to uproot deeply held beliefs about cancer screening with scientific data. Certainly, there are people over age 75 who have had cancers detected by routine screening, and gained several extra years of life because of treatment. And clearly, people over age 75 who have other risk factors for cancer, such as a family history, should continue to get screened regularly. But for the remainder, the risk of cancer, while increased at the end of life, must be balanced with other factors like a remaining life expectancy.

    A recent study suggests that doctors start to make more right decisions about who will truly benefit from screening—especially considering the explosion of the elderly.

    It's not an easy guess to make, but one that makes sense for the whole patient. Dr. Otis Brawley said, "Many doctors are ordering these tests purely to protect themselves against medical disputes(纠纷). We need to think about the good use of health care and stop talking about the rationing(定量配给制) of health care."

    That means making some difficult decisions with elderly patients and going against the misguided belief that when it comes to health care, more is always better.