Translation:She often helps me.
Reporting it now so it is reviewed and added as an acceptable answer.
Not accepted 2018.07.26.
經常 about 6~70%, I reckon is close to often. 常常 may correspond to usually, about 80% up.
When it comes to listening this sentence, [ta jingchang bang wo], Duolingo should not only accept 'SHE often helps me', but it also has to accept 'HE often helps me' in the translation since 'ta' in oral Chinese does not imply gender. In this case, it's not fair if it's strict to 'SHE' to refer 'ta' and make our translation answer wrong.
Negative. Here 經常 about 6~70%. Always means all the time, in Chinese we use 總是 or 每次