1. argument n.
【1】a statement you use to convince people that your opinion about something is correct
【2】a debate in which a number of people put forward different opinions.
【3】a conversation in which people disagree with each other angrily or noisily.
1) The incident triggered fresh arguments about the role of social insurance in China. 【 】 
2) Bob described how he got into an argument with the street vendor. 【】 
3) The evidence she uses to back up her arguments is not reliable. 【】 
2. represent v.
【1】to show, to describe
【2】to stand for
【3】to act officially for
1) He was well aware that he represented his nation in the race. 【】 
2) The play represents the collision of three generations. 【】 
3) The red lines on the map represent railways. 【】 
3. tough adj.
【1】strong and determined
【2】rough and violent
【3】difficult, demanding
1) He built up a reputation as a tough businessman.【】 
2) Whoever wins the election is to have a tough job getting the economy back on its feet. 【】 
3) You must be careful at night in this tough neighborhood.【】