I agree with Dongsu. However, just for fun, since you're a girl if you ever go to Korea these would be handy: 이게 얼마예요? [ee-gae eolmayaeyo?] ~> How much is this? 너무 비싸요, 좀 깎아주세요. [neo-mu pi-ssa-yo, chom ka-ka-ju-sae-yeo] ~> so expensive, cut the price please. 꺄아아아!! (scream) 변태!! [kyaaaaa!! (scream) pyeon-tae] ~> don't need to know the meaning, just do it when a weird guy making a weird move on you to attract attention. I think those, you MUST know. =)

I think it makes no sense. Can I ask you a question? What expression is useful in English? Perhaps, you don't answer it because this is too general. When we study, I think attitude is everything. I hope you will have a good attitude. I believe you will.