1 . A similar mechanism may perhaps ______ the fact that some group-living animals drive sick or injured individuals out of the group.

A．result from

B．bring out

C．account for

D．approve of

2 . Choose proper phrases and use their correct forms to complete the sentences.

bring up, bring about, bring in, bring out, bring back

1. The photographs __________________ many pleasant memories.
2. We need to __________________ a lot more new business to boost economy.
3. He is totally dedicated and __________________ the best in himself.
4. Interest-rate cuts have failed to __________________ economic recovery.
5. The officials decided to __________________ the issue of global warming at the meeting.