Hxen.com's tips：Every day persisted can learn English well!-->■Learn English Everyday■
expense – n. the cost of something
fee – n. a specific cost tied to an action
bank account – n. a service from a financial institution
app – n. an application used on a smart phone or tablet
bother – v. to take an interest in
tend - v. to usually do or make an effort
gross domestic product - n. the full amount of productivity of a nation
