21.  Because they want to touch with the new thing and new people.

22.  They like to have new thing in the job every day, don't like the same thing in the job .

23.  They want to see new things and different felling .

24.  They are used to do his favorite job and enjoy it.Someone like to changing his job frequently because his hobby is wide , and he like to receive new things and enjoy it, this help him to improve his experience and skill .

25.  They like trying new thing and overcoming difficuty .

26.  I think I like to often change jobs, because that I like to do new things, and it can make me know more.

27.  they can learn many new things from the new job.

28.  My idea is the second, the frontier is stable, but they aren't brisky .They don't aquire new things and envirment and opportunity.

29.  They change jobs because they are tired to do a same thing in a long period time, they take it for a challenge to face the new things and new peoples .

30.  They want to know new things, want to meet new people.