下列属于空想的是（）A、造永动机 B、莫尔的《乌托邦》 C、康帕内拉的《太阳城》 D、欧文

杂交育种运用的变异原理是[ ]

A．基因突变

B．基因重组

C．染色体结构变化

D．染色体数目变化

信息技术对教育有哪些影响？

Washington: The Bush administration has ______ for the first time that it may be willing to ______ a multinational force in Iraq to operate under the ______ of the United Nations as long as ______ by an American. The idea was described by Richard L.Armitage, the deputy secretary of state, as just"______" in discussions at the United Nations. It was first ______ publicly last week by Kofi Annan, the United Nations’ secretary general. Mr. Armitage’s remarks, made ______ to regional reporters and released by ______ today, represent ______ in course for the administration, which has until now insisted that all ______ matters in Iraq remain under total American control. Allowing the United Nations ______ would be intended to win the support of the Security Council for ______ authorizing the occupation of the country. In his remarks, Mr. Armitage ______ to discuss the plans ______, saying, "I don’t think it helps to ______ publicly fight now." But he described the arrangement under consideration as "a multinational force ______ "in which "the American would be the U.N. commander." On Monday, Defense Secretary Donald H. Rumsfeld was asked whether he could ______ American troops fighting ______ . His answer: "I think that’s not going to happen." But he went on to rule out only ______ meaning by the United Nations, whose troops wear blue helmets over a peacekeeping force in Iraq.

在进行食品安全事故调查时，首先应该（）.

A.采取防制措施

B.构成初步假设

C.核实诊断

D.调查三间分布