C （第一段：when he sees an old man at the bus stop）
B （第一段：So Mr.Green is surprised when he sees an old man at the bus stop with a big strong black umbrella in his hand.）
A
C (There isn‟t a cloud,and the sun is warm but not too hot)
B
C （第一段：when he sees an old man at the bus stop）
B （第一段：So Mr.Green is surprised when he sees an old man at the bus stop with a big strong black umbrella in his hand.）
A
C (There isn‟t a cloud,and the sun is warm but not too hot)
B