试述巨幼细胞贫血的治疗。

上市公司发行新股的申请文件一经报送，未经中国证监会同意，不得随意（）。

A.增加

B.撤回

C.更换

D.减少

下面对康乾盛世时期清朝疆域的表述错误的是[ ]

A．北界西伯利亚

B．东临太平洋

C．南及海南岛

D．西跨葱岭

鸟的下列结构中与“鸟的全身都为飞行而设计”含义不符的是 [ ]

A．体内有气囊

B．胸肌发达

C．前肢变成翼

D．有角质喙

深昏迷与中度昏迷最有价值的鉴别是（）

A.深浅反射均消失

B.对各种刺激无反应

C.无自主运动

D.大小便失禁

E.意识丧失

Scientists have for the first time used cloning to create human embryos that live long enough in a laboratory dish to have their stem cells harvested. The feat could set the stage for physicians to produce cells and tissues, tailored to a patient’s genetic identity that can treat a wide variety of human illnesses. The accomplishment also provides a road map for how to clone a person, an even more divisive undertaking.

The new work, performed in South Korea, represents "a major advance in stem cell research. It could help spur a medical revolution as important as antibiotics and vaccines", says Robert Lanza of Advanced Cell Technology (ACT), a company in Worcester, Mass., that’s also investigating the promising stem cell strategy called therapeutic cloning.

"However, now that the methodology is publicly available", Lanza adds, "I think it is absolutely imperative that we pass laws worldwide to prevent the technology from being abused for reproductive-cloning purposes."

While some fertility doctors and a religious cult have claimed success at creating a pregnancy via cloning, they’ve offered no convincing proof. In contrast, the South Korean research is being reported at the meeting of the American Association for the Advancement of Science in Seattle and will appear in an upcoming Science. "This is reality," says stem cell researcher John Gearhart of Johns Hopkins University. "He4’e is a bona fide, refereed journal saying that a human embryo has been cloned and a cell line derived from it."

Although ACT has not yet published a report of a cloned human blastocyst, Lanza says that the South Korean success is "consistent with our own results." Therapeutic cloning appeals to Lanza and physicians because cells made this way could have the same DNA as a patient’s cells do and thus avoid rejection after they’re transplanted.

Seeking a compromise that would permit this strategy to be pursued, many scientists have called for legislation that would ban cloning to produce a baby but allow the creation of cloned embryos to generate stem cells for research or therapies. "The debate has been very polarized," notes bio-ethicist Laurie Zoloth of Northwestern University in Evanston.

It can be inferred from the passage that human cloning（）

A. has not been so successful as some fertility doctors claim

B. will definitely be banned through legislations

C. has encountered huge technological and funding problems

D. is another project being implemented by South Korean scientists