急性胰腺炎时血淀粉酶（）。 A．增高最早 B．增高稍晚 C．增高最晚 D．不增高 E 发布时间：2017-07-02 16:12 │ 来源：www.tikuol.com 题型：单项选择题 问题： 急性胰腺炎时血淀粉酶（）。A．增高最早B．增高稍晚C．增高最晚D．不增高E．持续增高
题型：单项选择题 NH3还能与很多化合物通过配位键发生相互作用。例如：科学家潜心研究的一种可作储氢材料的化合物X是NH3与第二周期另一种元素的氢化物相互作用的产物，X是乙烷的等电子体；加热化合物X会缓慢释放H2，转变为化合物Y，Y是乙烯的等电子体。①化合物X的结构式为______________（必须标明配位键）。②化合物X、Y分子中，N元素分别发生了_____杂化。 查看答案
题型：单项选择题 Geography is the study of the relationship between people and the land. Geographers compare and contrast various places on the earth. But they also (51) beyond the individual places and consider the earth as a whole. The English word geography means "to describe the earth. " (52) geography books focus on a small area like a town or city. Others deal with a state, a region, a nation, or an (53) continent. Many geography books deal with the whole earth. Another (54) to divide the study of geography is to distinguish between physical geography and cultural geography. The former focuses on the natural world; the (55) starts with human beings and studies how human beings and their environment act (56) each other. But when geography is considered as a single subject, (57) branch can neglect the other. A geographer might be described as one who observes, records, and explains the (58) between places. If all places (59) alike, there would be little need for geographers. We know, however, that no two places are exactly the same. Geography, (60) is a point of view, a special way of looking at place.A．SomeB．ManyC．MostD．Few 查看答案