thank you for fast response!

yep, i had many questions and long conversation with visa officer when i came. so it can be even worse next time

im planning to go my home country for 2-3months. then i plannig to come back. i was thinking would multipe-entry visa help. but cause its not gonna help, i wont apply it.
i just have to have enough proves for the visa officer when i next time come....
i think i will leave 2months before my visa expires, i hope its a good sign to the visa officers...