wait on

wait on или wait upon  {v.}

1. обслуживать.

Sue has a summer job waiting on an invalid.

The clerk in the store asked if we had been waited upon.

2.  {formal} Посещать из вежливости или по делу.

We waited upon the widow out of respect for her husband.

John waited upon the President with a letter of introduction.

3. Следовать за.