Underlying = inner (underlying adj.在下面的, 隐含的 ，implicit 如 underlying meaning)
underpinning (基础, 支柱, 支撑 a support or foundation)
Unqualified (不合格的，无限制的，绝对的) = complete
utilitarian = functional (文中选) (utilitarian adj.功利的, 实利的, 功利主义的 n.功利论者 )
unqualified =complete;
utilitarian =functional
universally--without exception
unrestricted--unlimited
undergone--experienced
uniform
vigorous = strong
vexing = difficult (not sure) (vex: 使恼怒，使痛苦, puzzle, annoy)
volatile--
vast--immense
vast--great
vehicle--means
variability==tendency to change
withstand==persist >avoid/persist? 原文是：...brick withstood the weathering for a long time...
withstand=resist
wear--use
whatever --in any case/ at any rate/at all event
wary--cautious
way station--stop
？= yet 选项还有however / in addition.
yield--provide | 
