我想問我選呂郭碧鳳中學和蒙民偉書院那間機會大啲

I think 呂郭碧鳳的機會大

呂郭碧鳳機會大啲.....

呂郭碧鳳大啲....

I think you would have higher chance if you choose Lui Kwok Pik Fung. But your academic result is actually quite good, so why not try Mong Man Wai? I think you will be able to get in.