needDoes she have the skills needed for work of that sort?
requireWill you require a wake-up call in the morning?
mustThe meat must be cooked thoroughly.
essentialClean water is essential for a society's health.
fundamentalSome understanding of grammar is fundamental to learning a language.
indispensableThis book is an indispensable resource for teachers.
be a mustinformalThis book is a must for anyone who loves history.