第二节 完形填空(共10小题；每小题1分，满分10分)
阅读下面短文，掌握其大意，然后从每题所给的A、B、C、D四个选项中，选出能填入短文相应空白处的最佳选项。
Humans are mammals(哺乳动物). Most mammals are born able to do many things.
Some can walk within a few minutes of being born. They have to be able to run away if 1 is near. But human babies are born 2 . They need the care of adults to live.
