17、A) The tickets are more expensive than expected. 　　B) The tickets are sold in advance at half price. 　　C) Its difficult to buy the tickets on the spot. 　　D) Its better to buy the tickets beforehand. 　　答案 　　D) Its better to buy the tickets beforehand. 　　原文 　　M: Do we have to get the opera tickets in advance? 　　W: Certainly! Tickets at the door are usually sold at a higher price. 　　Q: What does the woman imply?