1. Buy at the old bottom or top. When a commodity falls to the old top or bottom, it is always a buying point protected by a stop loss order. When a commodity falls back to the old top for the first time, the second time and the third time, it is always safe to buy. When it falls to the same price for the fourth time, buying is quite dangerous because it almost always falls lower.

2. Commodity prices have broken through a series of tops in the past few weeks. Buy when a small trend or a big trend is reversed on a single commodity chart.

3. The commodity price has crossed the top of the previous week, and it has risen more than the most Big bounce in the process of falling from the top, so buy it when it falls back.

4. Buy when it rebounds from the bottom of the daily limit for the first time and exceeds Big bounce in the last big bear market.

5. Buy when the time exceeds the last rebound before reaching the lower limit.