This is a major undertaking, and the exposure is considerable.

It was a major undertaking.

She was very weak in fact because the surgery was a major undertaking and her system couldn't take it.

This is an important undertaking,

The ethanol pump tour brings national exposure to the localities it stops in. Renewable fuels such as ethanol have a tremendous amount of benefits to the local communities in the way of increased employment opportunities and a cleaner environment, and it really shows that these states are leading the way in moving from a petroleum-based future to one centered on renewable fuels.

He's a major league player, a major league hitter. He's going to be back up here.