进退自如

free to come and go (idiom) / to have room to maneuver

to go forward / to advance / to go in / to enter / to put in / to submit / to take in / to admit / (math.) base of a number system / classifier for sections in a building or residential compound

to advance or retreat / knowing when to come and when to leave / a sense of propriety

to retreat / to decline / to move back / to withdraw

to retreat; to withdraw / to reject; to return (sth) / to decline

self / oneself / from / since / naturally / surely

unobstructed / unconstrained / smoothly / with ease / freely

as / as if / such as