整理 I 後ろに決まった表現が来る副詞 教科書 p.92
Adverbs go with fixed grammar
接続：なかなか + Vない
forever without / quite. With negative: the expected thing is unlikely to happen; with the assertion: better than expected.
注意 / Note：Check the subject, tense and tone of both clauses; Avoid translating word for word from Vietnamese.
比較 / Compare：Compare with similar samples in the same article to choose according to nuance and connection. Same 課: 決して〜ない／めったに〜ない／必ずしも〜ない／とても〜ない／ぜひ／どうしても／まさか〜ない／いくら〜ても／もし〜ば／たとえ〜ても — these models are often mistaken for each other, read the 接続 line carefully and then decide.
バスがなかなか来ません。
The bus never came.
日本語はなかなか難しいです。
Japanese is quite difficult.
データが多すぎて、更新がなかなか終わりません。
There's too much data so updating takes forever.