categories, like 3D images, cartoons, paintings, etc.
如果你喜欢3D图片，动画，油画等等，就把你的题目复印下来。
你只要键入题目，就会按条目分别显示出所有相关结果，如3D图片，动画，油画等等。
如果你喜欢3D图片，动画，油画等等，只要键入题目，即可显示相关内容。
crowded together.
哪里人群拥挤，哪里就可能有昆虫传播疾病。
working on similar problems.
科学家在解决类似问题时总喜欢同其他科学家交流看法。
trees, enjoying the beauty of the scenery.
在古树林荫下，人们相当轻松地坐着欣赏美景。
down on fattening foods, but without any success.
医生建议我马上节食，于是我尝试着少吃增肥食品，但是毫无成效。
They later learned to
cut meat into thin strips and hang it up to dry in the hot air.
他们后来又学会了把肉切成薄片，挂在炎热的空气中风干。
Three ways were found
to keep meat from spoiling: salting, drying and freezing.
人们发现有三种方法可以使肉食不会变质：盐腌、风干和冷冻。
把肉食保存起来以备短缺之需同样困难。
tomorrow!
向东行，今天变成了昨天；向西行，今天变成了明天！
You can have days with
more or fewer than twenty-four hours, and weeks with more or fewer
than seven days.
有些天可能多于或少于24小时，有些星期可能多于或少于7天。
They could leave their
meat outside and eat it when they pleased.
生活在寒冷气候下的人们发现，冻肉不会变质。
If you make a five-day
drip across the Atlantic Ocean(大西洋), your ship enters a
different
time zone every day.
如果你用五天时间横渡大西洋，你乘的船每天都进入一个不同的时区。
你进入每一时区，时间就改变一小时。
Traveling west, you
set your clock back; traveling east, you set it ahead.
向西行，你把钟往后拨；向东行，则往前拨。
At first they probably
rubbed dry salt on it, but this preserved only the outside.
起初他们大概是把盐粒涂擦在肉上，但这只能保存肉的外层。
他们可以把肉露天放置，随时使用。
Later they may have
pickled(腌制) their meat by
soaking it in salt water.
后来，他们可能使用盐水浸渍的方法把肉腌起来。
Finding enough meat
was a problem for primitive man(原始人).
对原始人来说，找到足够的肉食是一个问题。
backward or forward.
你旅行的每一天都有25或23小时。
If you travel by ship
across the Pacific(太平洋), you cross the
international date line(国际日
期变更线).
如果你乘船横渡太平洋，你就会越过国际日期变更线。
Strange things happen
to time when you travel, because the earth is divided into twenty-four
time
zones(时区), one hour apart.
你旅行时在时间上会发生很多奇怪的事，因为地球分为24个时区，一区相差一小
时。
Keeping it for times when it was scarce(短缺的) was just as hard.
住在咸水域附近的人把肉腌起来。
As you enter each
zone, the time changes one hour.
你越过该线，就得把你的日历向后或向前改动一整天。
In hot, dry lands, men
found that they could eat meat that had dried while it was still on
the
bones.
在炎热干旱的地区，人们发现可以吃到还带着骨头的已经风干的肉。
By agreement, this is
the point where a new day begins.
根据协议，这是新一天开始的地方。
