20．听下面一段独白，回答第16-20小题．
16．When did the story happen？．
A．One evening
B．One morning
C．One afternoon
17．What were the other people doing when it happened？
A．They were talking．
B．They were walking．
C．They were sleeping．
18．Who took their food away？
A．A man did．
B．The writer did．
C．A bear did．
19．Where did they put their food？
A．Under a tree．
B．In a tree．
C．On the ground
20．What did the writer think of his experience？
A．It was very excited．
B．It was terrible．
C．It was really interesting．
