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Doing your homework is of _______ to your learning.
Exercise is __________ to your health.
We all have our own personal, ________ needs.
A birthday is a _______ day.
We have formed a history _______ to study our town's past.
The party was a great ______ event.
She was the _______ director of the company.
If you don't look after your money, you may have _________ troubles.
During space missions oxygen is _______.
The new football ground used __________ grass.