文档介绍：What are futures contracts ?
A futures contract is a contract to buy or sell an underlying commodity at a future time, at a price – the futures price – specified today.
The buyer takes a long position
（买方，多方，多头） （做多，持多头仓位）
The seller takes a short position
（卖方，空头，空方） （做空，持空头仓位）
Figure Profit Diagram for Futures Position Held to Expiration
(a) Long Futures
Profit
0
Initial futures price, F0
F0
Terminal futures price, FT
(b) Short Futures
Profit
F0
0
Initial futures price, F0
Terminal futures price, FT
In organized futures markets, contracts can be reversed before expiration by taking a position of opposite sign but equal magnitude in the same futures contract. Most futures contracts are, in fact, reversed in this manner prior to expiration.
Every futures contract entered into has two sides: a willing buyer and a willing seller. If one side of the contract makes a profit, the other side must make a loss. All futures markets participants taken together can neither lose nor gain – the futures market is a zero-sum game.
what are options ?
An option contract conveys the right to buy or sell an underlying commodity at a specified price within a specified period of time. The right to buy is referred to as a call option（买入选择权，买权）; the right to sell is a put option（卖出选择权，卖权）.
The specified price at which the underlying commodity may be bought (in the case of a call) or sold (in the case of a put) is called the exercise price or the striking price（执行价格） of the option. Most options may be exercised at any time, up to and including the expiration date. These are called American options（美式选择权）. If an option can only be exercised at expiration, it is termed a European option（欧式选择权 ）.
The buyer of an option pays the option writer (seller) an amount of money called the option premium or option price（选择权价格）. In return, the buyer receives the privilege, bu