地下核试验

underground nuclear test

-ly / structural particle: used before a verb or adjective, linking it to preceding modifying adverbial adjunct

earth / ground / field / place / land / CL:片[pian4]

underground / subterranean / covert

down / downwards / below / lower / later / next (week etc) / second (of two parts) / to decline / to go down / to arrive at (a decision, conclusion etc) / measure word to show the frequency of an action

pit / stone / nucleus / nuclear / to examine / to check / to verify

variant of 核[he2] / to investigate

nuclear weapons test

to test / to try / experiment / examination / test

nuclear test

experiment / test / CL:次[ci4],個|个[ge4] / to experiment / experimental

variant of 驗|验[yan4]

to examine / to test / to check