ばかりだ(Only) continue to, Keep on -ing, More and more

Occasionally, the adverbial particle ばかり is combined with verbs in their attributive form, to show that (A) is the only thing that is occuring. It may also imply that (A) is happening 'more and more', or that 'it keeps on (A)'. This phrase utilizes ばかり's standard meaning of 'only', and combines it with the auxiliary verb だ (or です).

As can be seen with these sentences, this use of ばかり is paired almost exclusively with verbs that describe some form of change (higher/lower, stronger/weaker, better/worse, faster/slower, etc).

If the speaker would like to express further information in a (B) part of the sentence, だ will simply get changed to its conjunctive form で, before continuing.

Caution

This use of ばかり is primarily seen with negative trends. However, this is not a grammatical rule, and positive trends may also sometimes appear with ばかりだ.