1, futures is a two-way transaction, and it will naturally not lighten the position based solely on liquidation. Because you don't know whether multi-position closing is a multi-position opening transaction or an empty position closing transaction. (How flat = how open or how flat = empty flat)

2. The only way to make money is to trade CSI 300 and IF at the same time. Two varieties trade in reverse. We can't consider the profitability of the operation direction simply based on whether the difference between IF and 300 is positive or negative.

3. The last question is the same as above. Although 300 is the subject matter of IF, IF reflects the trend of 300, especially futures, which trades in the futures market of 300. Simply trading one variety, no matter how the other goes, your profit-loss ratio is 1: 1.

Your last two questions involve hedging arbitrage, and you need some statistical knowledge. At least you need to know the spread between ETF and IF, and use this spread to arbitrage repeatedly. But now this range is not large, and it is difficult to make any profit without big funds.