According to the introduction, we become aware of the importance of smell when
A. we discover a new smell.
B. we experience a powerful smell.
C. our ability to smell is damaged
D. we are surrounded by odours.
审题，得出考察内容是在_______时候we become aware of the importance of smell. 定位词 the importance of smell, become aware. 定位在文章的斜体字介绍中：
The sense of smell, or olfaction, is powerful. Odours affect us on a physical, psychological and social level. For the most part, however, we breathe in the aromas which surround us without being consciously aware of their importance to us. It is only when the faculty of smell is impaired for some reason that we begin to realise the essential role the sense of smell plays in our sense of well-being.
重点内容为It is only when the faculty of smell is impaired for some reason that we begin to realize the essential role the sense of smell plays in our sense of well-being. 答案是when后面的内容提到the faculty of smell is impaired (损害，伤害)，即smell被损害的时候，对应正好就是C选项。其他均为无中生有选项。
The experiment described in paragraph B
A. shows how we make use of smell without realizing it.
B. demonstrate that family members have a similar smell.
C. proves that a sense of smell is learnt.
D. compares the sense of smell in males and females.
审题，得出考察内容是对Paragraph B中的experiment的描述。定位词experiment, paragraph B. 定位去原文中的B段
B Odours are also essential cues in social bonding. One respondent to the survey believed that there is no true emotional bonding without touching and smelling a loved one. In fact, infants recognise the odours of their mothers soon after birth and adults can often identify their children or spouses by scent. In one well-known test, women and men were able to distinguish by smell alone clothing worn by their marriage partners from similar clothing worn by other people. Most of the subjects would probably never have given much thought to odour as a cue for identifying family members before being involved in the test, but as the experiment revealed, even when not consciously considered, smells register.
跟实验有关的内容为：in one of well-known test, women and men were able to distinguish by smell alone clothing worn by the marriage partners from simiar… but as the experiment revealed, even when not consciously considered, smells register. 实验对象用smell去区分不同人身上的味道，但是却没有意识到使用了smell，因此正确答案为A。
其他选项：B.原文未提及family members have a similar smell. 只是提及similar clothing.为张冠李戴选项。 C和D均为无中生有选项。