By the time they reached the bus stop, the bus__________ for ten minutes.
A：had left
B：have left
C：had been away
D：have been away
澳门经济发展重要支柱产业是（ ）
2.4+5.7____5.7+2.4 52.1+72.1-43.65____43.65+(72.1-52.1)
12.34-2.9____5.73+4.1 35.6+4.6+7.01____35.6+4.4+7.21
