a. 不熟悉的

◆记忆方法一：
联想方式：
un+familiar

family/familiar/unfamiliar/familiarity/home/house/know/known/unknown
记忆：
1. family [ 5fAmili ] n. 家庭, 家族, 家属 Tom has a large family to support. 一大家人靠汤姆生活。
2. familiar [ fE5miljE ] 家庭的，当然是为大家熟悉的，adj. 熟悉的, 常见的。 The coming professor is familiar to all the students as he has been to the school twice. 要来的那位教授对所有的学生都很熟悉，他到这儿已来过两次了。Be familiar with 熟悉；be familiar to 对……来说是熟悉的。
3. unfamiliar [ 5QnfE5miljE] adj. 不熟悉的, 不常见的 What will you do with an unfamiliar letter? Delete it!你将怎样处理一封不熟悉的信件？删除！
4. familiarity [ fE7mili5Ariti ] n. 熟悉, 通晓 The familiarity shows that he has ever studies butterflies.他对蝴蝶如此熟悉表明他对蝴蝶做过研究。
5. home [ hEum ] n. 家, 住宅 adv. 在家, 回家, 在本国 East or west, home is best.东方西方，比不上家乡。 格言： There's no place like home. 金窝银窝，不如咱的狗窝。
6. house [ haus ] n. 房子, 住宅 vt.给...房子住 The housing conditions are much better in the urban areas now.现在城市地区的住房条件比以前好多了。
7. know [ nEu] v. 知道, 了解, 认识 I’m afraid I don’t know you.恐怕我并不认识你。
8. known [ nEun ] adj. 知名的, 大家知道的 The space flight made Mr. Yang Liwei well-known home and abroad.那次太空飞行使杨利伟先生天下闻名。
9. unknown [ 5Qn5nEun ] adj. 不知名的 One year ago, he was an unknown worker.一年以前，他还是一个默默无闻的工人。
另类阅读：
The family bought a new house near the well-known park. Though the kids were unfamiliar with the streets at first, soon the streets got familiar to them. They could leave their home for the park and even the unknown places to enjoy themselves.