Could U please tell me the differences between these two verbs? Can they be used interchangably? Thanks...
To extend is to stretch out (in length, time, effort, etc.):
He extended his arm across the table to reach the salt shaker.
The college extended the application deadline (from February to April).
We extended a welcome to the new neighbors.
To expand is to increase (in shape, size, volume, scope, etc.):
As she blew into it, the balloon expanded.
The campus expanded as the student population grew.
At first, our committee was only responsible for overseeing the disbursement of donations. Later, our scope expanded to fund-raising as well.
I hope this is useful,