不得不 [- - bù]have no choice but to; be bound to; be obliged to do sth.; cannot but; have to; cannot choose but; can't do better than; can't help but; can't keep from; can not refrain from; compel; force sb. to do sth.; have no option but to:
•¶不得不低头认罪 have to plead guilty
•¶ 时间有限， 我不得不赶紧。 As time is limited， I have to hurry.
•¶ 我不得不同意你的决定。 I cannot but agree to your decision.