【diploma】
meaning: a document showing that you have completed a course of study or part of your education.
example: Most of my friends are going to graduate the university. i hope they are able to get a diploma this year.
【speculate】
meaning: to buy goods, property, shares, etc. , hoping to make a profit when you sell them, but with the risk of losing money.
example: The price of resources like oil went up extremely begining of last year. Because many people had speculated in resources.
【contingency】
meaning: an event that may or may not happen.
example: He didn't bring any Metal and something like that to the airport, but he was stopped by the police officer. It was contingency for him and us at all.
【diplomat】
meaning: a person whose job is to represnt his or her country in a foreign countrym.
example: it's so hard to be a diplomat because that needs ability of speaking English.
