Nowadays more and more prople are keeping pets .Some pets are very pretty ,lovely and helpful .They can help people ____

Nowadays more and more prople are keeping pets .Some pets are very pretty ,lovely and helpful .They can help people _____ a lot of things .For example ,cats can help people to catch _____ ; dogs can help policemen to find the thieves ,helping blind men cross the street .Walking dogs is a good _____ and it can make old people feel less ____ .Animals such as fish ,tortoises are also people's pets .