US Driver
Road signs and speed limits for the Washington knowledge test
DOL does not say whether road signs are a separate part of the knowledge test or how many sign questions there are. State law requires the license exam to test your ability to see, understand and follow highway signs that regulate, warn and direct traffic (RCW 46.20.130).
Washington uses miles per hour (mph). When no other limit is set, the speed limit is 25 mph on city and town streets, 50 mph on county roads and 60 mph on state highways (RCW 46.61.400). The driver guide itself does not state this default; it gives, for example, 20 mph in school zones.
The Simplified Chinese driver guide has a section on traffic signs (4.12), covering common signs, work-zone signs and service signs. You can download it from DOL's driver guides page.