【单选题】

TomExample: (0) ) only seven (41) , so when he went (42) to camp with a lot of other small boys one summer, his mother thought he might be unhappy, and arranged for all his aunts and his grandmother and all his relatives to write (43) him, so that he (44) get a letter every day while he (45) away from home.

Well, of course he did not write to anybody while he was at camp.A、few days (46) he came back (47) , his mother saw him (48) some papers and asked him what (49)
"Oh", he said, "they are the letters I got while I was (50) the camp, I did not have time to look at them while I was there.\
A．before
B．after
C．when