■ signature

可以当作形容词，意思是“标志性的”。

• Los Angeles' signature palm trees洛杉矶那些标志性的棕榈树
• New York's signature skyscrapers纽约那些独特的摩天大楼
• Two of his (Bush's) signature domestic proposals: Overhaul of Social Security and of immigration laws. (US News & World Report, Feb. 11, 2008, p.12)布什的两大内政主张，即整顿社安制度和移民法。

• what 与 how
• what 与 who
• when
• where
• where it counts
• whether
• whether 与 if
• which
• which
• while
• who
• who
• who
• whoever
• why
• -wide
• wide
• widow
• win
• wipe
• -wise
• wise men
• wish
• wish
• with