U

under - prep. below; below the surface of; less than; as called for by a law，?
agreement or system ("The river flows under the bridge." "Such action is not?
permitted under the law.")

understand - v. to know what is meant; to have knowledge of?

unite - v. to join together?

universe - n. all of space， including planets and stars?

university - n. a place of education that usually includes several colleges and
research organizations?

unless - conj. except if it happens; on condition that ("I will not go， unless the rain
stops.")?

until - conj. up to a time; before?

up - ad. to， in or at a higher position or value?

urge - v. to advise strongly; to make a great effort to get someone to do something?

urgent - ad. needing an immediate decision or action?

us - pro. the form of the word "we" used after a preposition ("He said he would
write to us.") or used as an object of a verb ("They saw us yesterday.")?

use - v. to employ for a purpose; to put into action?

usual - ad. as is normal or common; as is most often done， seen or heard
?
?

V

valley - n. a long area of land between higher areas of land

value - n. the quality of being useful， important or desired; the amount of money
that could be received if something is sold?

vegetable - n. a plant grown for food?

vehicle - n. anything on or in which a person or thing can travel or be transported，
especially anything on wheels; a car or truck?

version - n. the form of something with different details than earlier or later forms?

very - ad. extremely ("He was very late.")?

veto - v. to reject or refuse to approve?

vicious - ad. bad; dangerous; showing harm or hate?

victim - n. someone or something that is injured， killed or made to suffer; someone
who is tricked?

victory - n. a success in a fight or competition?

village - n. a very small town?

violate - v. to fail to obey or honor; to break (an agreement)?

violence - n. the use of force to cause injury， death or damage?

visit - v. to go to or come to a place for a short time for friendly or business reasons?

voice - n. the sound made by creatures， especially humans， for speaking?

volcano - n. a hill or mountain around a hole in the earth’s surface that can explode，
sending hot， melted rock and ash into the air?

vote - v. to choose a candidate in an election; n. a choice or decision expressed by
the voice， by hand or by writing