循环使用

recycle / to use in cyclic order

to follow / to adhere to / to abide by

to cycle / to circulate / circle / loop

surname Huan

ring / hoop / loop / (chain) link / classifier for scores in archery etc / to surround / to encircle / to hem in

to make / to cause / to enable / to use / to employ / to send / to instruct sb to do sth / envoy / messenger

to use / to employ / to apply / to make use of

to use / to employ / to have to / to eat or drink / expense or outlay / usefulness / hence / therefore