单项选择题

C

Going, Going, Gone! The Haynes Middle School Parent-Teacher Organization invites you to attend our latest fund-raiser. The Fourth Annual Haynes School Auction (拍卖)! Saturday, May 10 6:00 p.m. — 11:00 p.m. in the school hall 6:00 p.m. — 6:30 p.m.: All items for auction are previewed. 6:30 p.m. — 7:00 p.m.: Silent auction begins. 7:00 p.m. — 7:30 p.m.: Highest bidders(出价人) from silent auction are determined. 7:30 p.m. — 11:00 p.m.: Main auction begins. Items up for bid in the silent auction range in value from $5 to $30. Items up for bid in the main auction include the following: Airline tickets to a place of your choice Weekend getaways at first-class hotels Season tickets to the Chicago Bears football game $50 gift tickets to local gift shops, restaurants, and salons Theater tickets to The Merchant of Venice Don’t miss the boat! Book your tickets today. Last year, tickets sold out in five days! Tickets are sold on a first-come, first-served basis. $15 per person. All the money from the auction will be given to the Haynes School computer lab.

The phrase "first-come, first-served" tells you that______.