difference/indifference/different/indifferent/differ/difficult/difficulty/dilemma/fiction/hard/hardship
记忆：
1. differ [ 5difE] dif-fer vi. 不一致, 不同 People differ from each other.人与人不同。
2. difference [ 5difErEns ] n. 不同，差异 There must be some difference between two words.两个单词之间肯定有差异。
3. different [ 5difrEnt ] adj. 不同的 What he did was different from what said.他言行不一致。
4. 否定前缀in-, indifferent [ in5difErEnt ] 有没有都没什么不同 adj. 无关紧要的 I feel it indifferent for him to agree with us.我觉得他同不同意我们的意见并不重要。
5. indifference [In5dIfrEns] n. 不关心，冷漠 The host’s indifference annoyed the visiting guests.主人的冷漠惹恼了来访的客人。
6. 词根fic表示“做”，di, de-, 不；difficult [ 5difikElt ] 不易做的，困难的 adj. 困难的 The terrorism is too difficult to remove by force.恐怖主义很难用武力清除。 All things are difficult before they are easy. 事必先难后易。 格言： Nothing in the world is difficult if you set your mind to it. 世上无难事，只怕有心人。
7. difficulty [ 5difikElti ] n. 困难 We have some difficulty with the project.那项工程我们有些困难。
8. fiction [ 5fikFEn ] 做出来的，n.虚构, 编造, 小说 Waltner was famous for his science fictions.华尔纳因其科幻小说而著名。
9. dilemma [ di5lemE7 dai- ] di-lem-ma 音“勒马之地”，进退两难；n. 进退两难的局面, 困难的选择 About the issue of Iraque, the Bush government is in a dilemma though it refuses to admit it.关于伊拉克问题，布什政府处于两难境地，然而它不愿承认。
10. hard [ hB:d ] adj. 硬的, 困难的, 艰苦的, adv.努力地, 辛苦地 It’s hard for us to cut the hard stone into halves.我们很难把坚硬的石头割成两半
11. hardship [ 5hB:d7Fip] n. 困苦, 艰难, 辛苦 Any hardship can be overcome in this way or that.任何艰难都有办法克服。
另类阅读：
We have great difficulty in telling the difference between the twins. They differ so slightly that everyone finds it hard to call them by names except their parents.