required

all, constant, proper, protected, regular, sick

All required documents were submitted before the deadline yesterday.

experiment, meeting, police, reply, tie, time

The police required a detailed statement from the witness about what happened that night.

attention, class, course, dictionary, environment, john, uniforms, women

The required course on environmental science was challenging but very informative.

in

A valid passport is required in most countries for international travel.

legally, urgently

The documents were legally required before we could proceed with the application.