Investing a little bit so that someone knows where you stand, so that someone knows that you like them, so that someone knows you're open to a date, so that someone knows that you'd like to see them for a second date, so that someone knows that you find them attractive, sexy, appealing as a human being.
投入一點,讓對方知道你的立場,讓對方知道你喜歡他,讓對方知道你願意和他約會,讓對方知道你願意和他第二次約會,讓對方知道你覺得他有魅力、性感、有人情味。