1.________ (compare) to other animals,hibernating bears look

1.________ (compare) to other animals,hibernating bears look different.
________ (compare) hibernating bears to other animals,we may easily find the difference.
2.With my poor English,I’m afraid I can’t make myself _____ (understand) the long story.
With my poor English,I’m afraid I can’t make myself _____ (understand) by the audience.
3.Some experts argue that the writing section _____ (add) to the entrance exam will be effective in testing the students’ ability.
Some experts remark that the writing section in the latest entrance exam is difficult,_____ (add) to students’ and parents’ anxiety about their exam results.
4._____ (expose) to advertising too often tends to make children materialistic.
Children ______ (expose) to advertising too often will become materialistic.
_______ (expose) oneself to advertising too often is an important cause of becoming materialistic.
5._____ (see) the guys bully the young boy,one of the passers-by immediately contacted the police.
When _____ (see) by the tough guys,the young boy would be bullied by them.
______ (see) the tough guys who often bullied the young boy,I went home with him yesterday.