I you wanna say it pleasantly you should say :Piękna dziewczyna or śliczna dziewczyna You can say 'laska' BUT it's not always perceived positively, it's rather used in teenage slang and some girls...
The effects of Polish immigration in the UK are things such as:Negative: Over crowding/over population Not enough spaces in universities/collages/schools for British pupils Not enough work for...