在生产和生活中，人们常把密度作为选材的主要考虑因素之一．下面那项是主要从密度的角度考虑选材的（　　）

为实现国家大一统，汉武帝在思想文化方面采取的措施是（    ）

如图，右边的两个图形分别是由左边的物体从两种不同的方向观察得到的，请在这两种平面图形的下面填写它们各是从什么方向看得到的｡

①____ ②____ ．

    There is a man and he calls the police when he loses a pet. He a lways asks the police to help him look for it.

    “I lost my pet bird，”he tell the police one day.“She can sing songs. Can you find her for me?”

    “I'm sorry，”the policeman says.“It isn't our job（工作）to look for birds. If you leave a window open in your house，the bird may come back.”

    Another time，the man calls the police and says，“I lost my cat. （A）你能帮我找到他吗？He can  talk. ”

    “I'm sorry，”the policeman says.“（B）It isn't our job to look for cats. You should put the telephone down quickly. Maybe（也许）he is calling you now and tells you where he is. ”

I can____(run, running) very fast.