还原剂

reducing agent

surname Huan

still / still in progress / still more / yet / even more / in addition / fairly / passably (good) / as early as / even / also / else

to pay back / to return

to restore to the original state / to reconstruct (an event) / reduction (chemistry)

surname Yuan / (Japanese surname) Hara

former / original / primary / raw / level / cause / source

dose (medicine)