Answer:
HS⁻ and OH⁻ 
Step-by-step explanation:
Per the Brønsted-Lowry theory, a base is a substance that can accept a proton from another substance 
 HS⁻ + H₂O ⇌ H₂S + OH⁻ 
base base 
The reaction above is an equilibrium reaction. 
In the forward reaction, HS⁻ is acting as a base, because it is "accepting" a proton from water to become H₂S. 
In the reverse reaction, OH⁻ is acting as a base, because it is "accepting" a proton from H₂S to become H₂O.