31.Frustrated by these restrictions,Subra left her job in 1981,created her own company,and has devoted the past two decades to helping people fight back against giant industrial polluters.
frustrate意为“使沮丧，使挫败“。devote...to doing sth.意为“把……用于做某事，致力于做某事“。fight back against意为“奋力抵抗，还击“，其后的宾语即为抵抗的对象，同时也往往是听音的重点。也可以只说fight back，表示“还击，抵抗;抑制“。如:
1) Victims of discrimination often don't have the power to fight back。
2 ) She fought back her disgust.
fight sb/sth. off意为“击退，竭力摆脱“。如:
They had to fight off the crowds to get out of the theater。
I'm fighting off a cold.
fight sth. out意为“通过争辩(争斗)解决“。如:
The conflict is still being fought out.