1. Direct contract: A direct contract refers to an instant delivery contract, in which the buyer and the seller immediately conclude a transaction and perform the contract. In the foreign exchange market, spot delivery of foreign exchange transactions is a direct contract. There is no time limit for direct contracts, and the delivery time is generally T+0 or later.

2. Basis contract: Basis contract refers to the price difference between the derivative contract and the spot subject matter, also known as basis. Basis contracts allow investors to trade according to the price changes of the subject matter, and earn profits by making long or short basis. Basis contract is usually a combination of spot market and futures market, which can be used for arbitrage and risk hedging.

3. Futures contract for differences: Futures contract for differences refers to the price difference between futures contracts of the same variety with different delivery periods. Futures contracts with different maturities are usually traded between futures contracts. Investors can profit by shorting or shorting the futures gap, and use the price fluctuation in the futures market for arbitrage or risk management. Direct contract is an immediate delivery contract, basis contract is a difference contract between spot market and futures market, and futures contract is a difference contract between futures contracts with different maturities. They are different in terms of transaction mode, delivery mode and term.