If the second sentence is your teacher's original words, I can only say that he has never done futures.

When the price rises, the bulls are bound to make a profit. Because you used to buy at a low price, but now you sell at a high price. Hedging the original long position with short positions is called locking orders.

At first, the bears were bearish, but the price did not fall but rose. So bears can buy and close positions at high prices. The essence is to sell at a low price and buy at a high price, so the bears lost money.

The secret here is Blash.