Today, we live in a world where GPS systems, digital maps, and other navigation apps are available on our smart phones. (1)_____of us just walk straight into the woods without a phone. But phones (2)_____ on batteries, and batteries can die faster than we realize. (3)_____ you get lost without a phone or a compass, and you (4)_____ can’t find north, we have a few tricks to help you navigate (5)_____ to civilization, one of which is to follow the land.

　　When you find yourself well (6)_____ a trail, but not in a completely (7)_____ area, you have to answer two questions: Which (8)_____ is downhill, in this particular area? And where is the nearest water source? Humans overwhelmingly live in valleys, and on supplies of fresh water. (9)_____ , if you head downhill, and follow any H₂O you find, you should (10)_____ see signs of people.

　　If you’ve explored the area before, keep an eye out for familiar sights—you may be (11)_____ how quickly identifying a distinctive rock or tree can restore your bearings.

　　Another (12)_____ : Climb high and look for signs of human habitation. (13)_____ , even in dense forest, you should be able to (14)_____ gaps in the tree line due to roads, train tracks, and other paths people carve (15)_____ the woods. Head toward these (16)_____ to find a way out. At night, scan the horizon for (17)_____ light sources, such as fires and streetlights, then walk toward the glow of light pollution.

　　 (18)_____ , assuming you’re lost in an area humans tend to frequent, look for the (19)_____ we leave on the landscape. Trail blazes, tire tracks, and other features can (20)_____ you to civilization.

答案精析：空格所在句的前一句说到“寻找（look for）人类居住的标志”，这里的“标志”指的就是此题后面的gaps，因此此空应填入look for的同义词，正确答案为C。

错项排除：此段并未说到要在空隙（gaps）上架一座桥，A错。空格所在句的后一句提到，我们要沿着这些空隙寻找出路，因此不能填入“避免”或“分开”，B、D错。