The cryptocurrency market is volatile, and you need to know how to buy and sell to make big money. In February and March of this year, many high-quality altcoins increased several times or even ten times. At that time, everyone should reduce their positions in the coins with larger increases, control their positions, and keep some U in hand, so that they will not be so hesitant and lose so much profit when the market falls back. If you have U in hand now, you can once again buy the potential coins that have fallen back to the bottom and have been developing well.