英和和英

attendance is mandatory

attendance is obligatory

to be necessary

do the necessary

to meet a need―meet a want

to meet a need

of something, to be needed

according to the need

Is required

approval required

required reading

require a deposit

to meet the need―fill a need―minister to one's needs

a required subject

by necessity

You will be required to do so.

revision required

to supply the demand―meet the demand

distributional requirements

It's necessary.

Is a signature necessary?

in case of necessity

to urge （on one） the necessity of something―impress upon one the importance of something

to meet the demand―supply the demand

to supply the demand―meet the demand

urgently needed

have need of

immediate needs

a key point

to be pressed by necessity