unmarked

adj.

没有标志的，未被注意到的；

1. She handed him an unmarked card.
   她递给他一张无标志的卡片。
2. A few cops prowled in marked and unmarked cars.
   几名警察乘坐有标志和无标志的汽车在暗中巡查。
3. his retirement was not allowed to go unmarked.
   他的退休是不容忽略的。

Unmarked: The Politics of Performance
The Emergence of the Unmarked
Mortality Rates of Marked and Unmarked Fawns
THE EMERGENCE OF THE UNMARKED IN SECOND LANGUAGE PHONOLOGY
The emergence of the unmarked: Optimality in prosodic morphology
unmarked: An R Package for Fitting Hierarchical Models of Wildlife Occurrence and Abundance
Generation of unmarked directed mutations in mycobacteria, using sucrose counter-selectable suicide vectors.
Use of a flexible cassette method to generate a double unmarked Mycobacterium tuberculosis tlyA plcABC mutant by gene replacement
An nptI-sacB-sacR cartridge for constructing directed, unmarked mutations in gram-negative bacteria by marker exchange-eviction muta...
Specialized transduction: an efficient method for generating marked and unmarked targeted gene disruptions in Mycobacterium tubercul...