转入地下

to go underground / to turn to secret activities

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

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

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

see 轉文|转文[zhuai3 wen2]

to turn / to change direction / to transfer / to forward (mail) / (Internet) to share (sb else's content)

to revolve / to turn / to circle about / to walk about / classifier for revolutions (per minute etc): revs, rpm / classifier for repeated actions

to enter / to go into / to join / to become a member of / to confirm or agree with / abbr. for 入聲|入声[ru4 sheng1]

underground / subterranean / covert

to change over to; to shift to; to switch to