No,209 : ~하지 않을 수 없다.

No, 209

= be forced to = be obliged to = be compelled to
= cannot help ~ ing = cannot but 동사
= cannot choose but 동사 = cannot avoid ~ ing
= have nothing to do but 동사원형 = have no choice but to 동사원형
= have no alternative but to 동사 = nothing remains but to 동사원형
= There is nothing for it but to = cannot keep/abstain/refrain from ~ ing
= be bound/ forced/ compelled/impelled/obliged/constrained to 동사
ex) I could't admiring him. 그에게 감탄하지 않을 수 없었다.