It is necessary to wear a helmet while riding a bike.
It is necessary to wear a helmet when riding a motorcycle.
Strict regulations are necessary for maintaining order.
She avoids eating outside whenever necessary.
We avoid rushing decisions whenever necessary.
They avoid using harsh words whenever necessary.
I stopped buying unnecessary things in the long run.
We avoid spending money impulsively whenever necessary.
I study English because it's very important and necessary.
Do you know why it is necessary to prevent flu in New York?
Do you know why it is necessary to prevent air-borne diseases?
Do you know why it is necessary to prevent water-borne diseases?
She avoids checking emails during family time whenever necessary.