根据短文内容，从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

    It is impossible to know when you might find yourself lost in a forest. If you know what to do, you can survive in a forest without much trouble; but if you are not prepared, survival can be much less likely.

Keep fear at bay

    It is completely natural to be afraid when you are faced with a survival situation. ____ The more your fear overcomes you, the lower your chances are of survival, as your mind is going to become clouded and panic may set in.

Stay warm

    Obviously, the low body temperature is one of the primary dangers you face when you must survive in the forest____ Never stop to sleep or quit moving around unless you have appropriate shelter.

Know how to make a fire

    Obviously , if you have a lighter or matches, this is not a problem. But if not, you can attempt to use a dry narrow pointed stick and a dry flat piece of wood. ____ This requires a great deal of work, but if done correctly, you will succeed.

Make some shelter

    ____ The easiest way to provide protection is to find a fallen tree and cover it with other branches and brush so that you can stay in the natural pit underneath the tree trunk.This is a very important aspect of being able to survive in the forest.

Stay put unless you know exactly where you are

    If you can build a stable shelter and start a fire, you can survive in the forest for several days. ____ If you know where you are, travel as far as possible during the day while making sure you stop long enough before dark so that you can build another shelter.

设椭圆中心在坐标原点，A（2，0），B（0，1）是它的两个顶点，直线y=kx（k＞0）与AB相交于点D，与椭圆相交于E、F两点．

（Ⅰ）若 $\overrightarrow{ED}=6\overrightarrow{DF}$ ，求k的值；

（Ⅱ）求四边形AEBF面积的最大值．