1. Once cells have specialized, on their way to becoming skin or eye or udder cells, most of the genetic instructions to make a full being are turned off.
    一旦细胞特化，进入成为皮肤细胞、眼睛细胞或乳腺细胞的过程，大部分长成完整个体的基因指令就被关闭。

2. Let us suppose that you are preparing a meal and keeping an eye on the baby at the same time.
    假设你在做饭，同时又在照看孩子。

3. I made a diagram to show how the eye works.
    我画了一张简图说明眼睛是如何工作的。

4. If one group of people were disturbed from their eye-movement sleep for several nights on end,
    如果有两组人，一组人连续几夜在眼球队活动时被叫醒；

5. In some countries no major business is conducted without eye contact, requiring face-to-face conversation.
    在有些国家里, 没有当面接触就做不成大生意, 需要面对面的交谈。

6. It is common to look up, down, and all around when speaking to others, and not have eye contact at all times.
    而你自己对别人说话时，向上、向下、以及向四周看看，这都很平常，你不必一直保持与对方目光的接触。

7. I reach for the light switch, and as it silently lights the scene, I return to the bed to observe the patient with an unemotional, medical eye.
    我伸手去开灯。灯静静地照亮了整个病房，我走回病床边，用无动于衷的、医生的目光观察着病人。