This question fails to explain that the reason for hedging is the problem of the topic. From March to May, spot prices and futures prices showed opposite trends (spot prices fell, futures prices rose), which is unreasonable, because futures prices are expectations of future spot prices, so futures prices should show the same trend as spot prices (although most of the time the changes are different).
As an exception, what he meant by selling futures should be: liquidating the established future positions and making profits in 30 yuan.