3週6日目 上がる一方だ
Development・time・result
接続：V辞書＋一方だ
just keep changing in one direction
注意 / Note：一方だ／ばかりだ says the trend continues; つつある describes an ongoing process of change and favors writing.
比較 / Compare：Same song: 〜ばかりだ／〜つつある. These models are often mistakenly chosen for each other — carefully read the 接続 and nuances above and then decide.
よく出る形 / Common form：動辞書形＋一方だ。One way ONLY, no turning back. Or go with 増える・減る・悪くなる・上がる.
物価は上がる一方だ。
Prices keep increasing.
人口は減る一方だ。
The population continues to decrease.
この分野への関心は高まる一方だ。
Interest in this field continues to grow.