「Always only ~, and nothing else.」 Often used to say something that is considered bad.
例:
1. 弟は毎日あきずにカップラーメンばかり食べている。
My younger brother eats cup ramen every day without ever getting tired of it.
2. 寮では同じ国の人とばかり話さないで、いろいろな国の人と会話したほうがいい。At the dorm, don't just talk to people from your own country—try talking with people from different countries.
3. ありがとうございます。いつもいただくばかりで、お返しもできなくてすみません。Thank you. I'm always the one receiving, and I'm sorry I can't return the favor.
4. 子どもはただ泣いているばかりで、何があったのかわからなかった。The child was just crying, and I couldn't tell what had happened.
5. この写真の女の子は今どうしているのでしょう。彼女の幸せを祈るばかりです。I wonder how the girl in this photo is doing now. All I can do is pray for her happiness.