问题 选择题

吞噬病菌的细胞、在显微镜同一视野中所见到数目最多的血细胞分别(  )

A.红细胞、白细胞

B.白细胞、红细胞

C.精细胞、血小板

D.淋巴细胞、脂肪细胞

答案

血液中的白细胞有多种,有细胞核,比红细胞大,数量少,每立方毫米血液中有5000--10000个;当身体某处受伤,病菌侵入时,有些白细胞可以穿过毛细血管壁,聚集到受伤的部位,吞噬病菌,同时,伤口周围出现红肿现象,叫发炎;可见白细胞对人体起着防御和保护的功能.血液中的红细胞无细胞核,呈两面凹的圆饼状,成年人每立方毫米血液里红细胞的数量,男子为500万个左右,女子平均为420万个左右,在三种血细胞中红细胞的数目最多.

故选:B

单项选择题
单项选择题

Henry Kissinger may be the most successful, certainly the most flamboyant, Secretary of State to hold that office in modern times. When he was appointed in the late 1960’s, there were no American ties with Communist China, Vietnam and Berlin seemed ready to draw the United States into a third world war, and Russia was seen as "the enemy".

But all this has changed, and Henry Kissinger caused much of the change; in 1971, he made his first trip to China, a trip that was the beginning of the current ties between the United States and China. He brought the United States and Russia closer together on major issues by the policy he called "detente", literally meaning a relaxation. His philosophy was always to talk and to bring together. With these two policies, Kissinger did much to draw attention away from any possible Russia-American friction.

In 1973 he made his first visit to Egypt. Here he was able to begin U.S. relations with Egypt. He used his contact later to begin the sort of talks that the American press called "shuttle diplomacy". For ninety-nine days, he "shuttled" back and forth on flights between Cairo and Jerusalem to work out a step-by-step withdrawal of Israeli troops from the Sinai desert. His wit, his careful approach to detail, and his presence made "shuttle diplomacy" work. It was the only successful approach to Mid-east peace in the thirty years since the state of Israel was founded.

Another major work was the Strategic Arms Limitation Talk. Though his term in office passed with the treaty unsigned, Kissinger left a draft of the treaty to which the Russians had already agreed. The SALT treaty spelled out a one-tenth reduction in nuclear arms, a major accomplishment by any standard, even if one does not consider all the other conditions and limitations included in the treaty.

Even though he successfully helped bring an end to the Vietnam War, Kissinger’s final days in office were affected, as was the entire executive branch in one way or another, by the scandals of the Nixon White House. Kissinger’s critics point to his role in placing wiretaps on the phones of reporters and officials and to what they consider his "high-handed" approach to setting foreign policy. But Kissinger, during the last few months of the Nixon presidency, limited the effects of American domestic problems on our foreign policy. He continued talks in the Middle East. He continued close contact with the Soviet Union.

History will decide in the final view, as Kissinger--and many presidents--often said, on the value of his service. Whatever they decide, whether his actions are finally to be considered wise or foolish, he had a personal vision that will he difficult to match.

It can be inferred from the last paragraph of the text that()

A. "shuttle diplomacy" seriously affected the SALT treaty

B. Watergate scandals made Kissinger ineffective

C. some of the things Kissinger initiated are still being worked out

D. Kissinger is an outstanding politician but unable to cope with domestic affairs