有关理财的简单对话 — 英语填空题
题目
根据对话语境和常识补全句子（第二空填英文数字）。
A: I get 20 yuan pocket money every week. I want to buy a model plane. It's 50 yuan.
B: You don't have enough money now. You'd better s___ it and not buy snacks. If you save all your pocket money, you can buy it in ___ weeks.