3. NG

　　4. T 见第六段 Molecules that look almost identical can smell very different — such as alcohols， which smell like spirits， and thiols， which smell like rotten eggs.identical 一词是完全相同的意思。这句话是说alcohols和thiols的分子结构看起来一样，但是它们的味道却相去甚远。

　　5. Luca Turin 文章第二，三和七段均可看出Luca的理论即人类的鼻子是通过感觉气味分子的震动来分辨气味的。

　　6. Virginia 见第四段。

　　7. tongue 见第五段 This molecular ’lock and key’ process is thought to lie behind a wide range of the body’s detection systems： it is how some parts of the immune system recognise invaders， for example， and how the tongue recognizes some tastes.

　　8. the atoms 见第八段 This would explain why isotopes can smell different： their vibration frequencies are changed if the atoms are heavier.

　　9. vibration-assisted electron tunneling 见第九段 The question is whether this is possible in the nose， says Stoneham’s colleague， Andrew Horsfield. 句中的代词this指句首的vibration-assisted electron tunneling。

　　10. Andrew Horsfield 见第九段结尾。

　　11.proper experimental verification 见第十三段。

　　12.their computed vibrations 见第十四段。