单项选择题 （）外部中断 0 允许中断的 C51语句为 ______。 A. RI=1 B. TR0=1 C. IT0=1 D. EX0=1

未知题型 听力原文：W: Good morning, can I help yon?M: Yes, I'm looking for a Christmas present for my girl frienD.W: So you'd like to choose a dress here?M: But I don't know what's in now?W: How about this white dress? It's a new arrival.M: That's nicE.How much does it cost?W: $250.M: Mmm, I think that's a little expensivE.W: How about the red one? It's 20% off, now just $80.M: Great, I think I'll take this onE.(8)A.In a book storE.B.In a hotel.C.In a grocery.D.In a department storE.

单项选择题 解决一对多配送的最短路线问题时通常可采用( )方法。