A: Ultraviolet light is harmful to our skin.
B: So you better wear some sunscreen when you are out in the sun.
ultraviolet
a. 紫外线的

A: Were you all able to come to a unanimous decision?
B: No, one person disagreed with us.
unanimous
a. 全体一致的，一致同意的

A: I didn’t think that you would be able to carry the heavy box.
B: Well, you shouldn’t have underestimated my strength.
underestimate
vt. 对……估计不足，低估
n. 估计不足，低估

A: I don’t understand the ideas that underlie your essay.
B: Oh, let me explain them again.
underlie
vt. 构成……的基础（或起因），引起

A: What is the underlying reason for doing this journey?
B: To explore a new region of the country.
underlying
a. 含蓄的，潜在的

A: Philip always undermines my opinions.
B: Don’t worry, he is just trying to start an argument.
undermine
vt. 1。暗中破坏，逐渐削弱；2。侵蚀……的基础

A: Even my underwear got wet in the rain.
B: That must have been a heavy shower.
underwear
n. 衬衣，内衣

A: Doctor, do I really need to undress ?
B: Well, I need to examine your back.
undress
vi. 脱衣服
vt. 除去……的衣服
n. 裸体（或半裸体）的状态

A: There is a high rate of unemployment in my region.
B: But I hear that it is not as bad as last year.
unemployment
n. 失业，失业人数

A: Haven’t you finished the book yet?
B: No, the plot is just unfolding .
unfold
vi 1。展开，打开；2。显露，展现
vt. 展开，打开

A: Let’s all sing a song.
B: Do you think that will help to unify our group?
unify
vt. 1。使联合，统一；2。使相同，使一致

A: Gavin unleashed some nasty comments at me.
B: Don’t mind him, he is always rude.
unleash
vt. 1。发泄，发出；2。解带子放开

A: Did you hear the latest news?
B: No, can you update me on the details?
update
vt. 更新，使现代化
n. 最新信息

A: You always stick to your word.
B: Yes, I like to uphold my principles.
uphold
vt. 支持，维护，赞成，认可

A: There was an uprising in my country in the 1920s.
B: Was that when you declared an independent nation?
uprising
n. 起义，暴动

A: There will be uproar if my homework is not submitted in time.
B: Oh, but you are usually such a good student.
uproar
n. 吵闹，喧嚣，骚乱

A: I heard that some toxic uranium was dumped into the sea.
B: Yes, it is shocking news.
uranium
n. 铀

A: There is a terrible smell of urine in this room.
B: I agree, but I don’t know where it is coming from.
urine
n. 尿

A: The usher directed me to the wrong seat.
B: Oh, I think that he has just started the job.
usher
n. 引座员，招待员，迎宾员
vt. 1。引，领，陪同；2。预报（……的来到），宣告；3，创始，开辟

A: Can we make this dish for dinner tonight?
B: No, I don’t have the right cooking utensils .
utensil
n. 器皿，器具