と
Particle, Conjunction
1. if, when
2. and
3. with
4. used for quoting (thoughts, speech, etc.)
See と金, Shogi term, Abbreviation
5. promoted pawn
つくづく, 熟, 熟熟, 熟々, つくつく
Adverb, Adverb taking the 'to' particle, Usually in kana, Onomatopoeic or mimetic word
1. deeply, keenly, severely, completely, utterly
2. intently, carefully, closely, attentively
彼は、自分の不幸をつくづく考えた。