看向世界SpotWorld: briefly explain the differences between ‘a movement along the demand curve’ and ‘a shift in the demand curve’ with diagram

Movement along the demand curve.
沿着需求曲线运动。

Movement along the demand curve will cause a change in both the price and quantity demanded. For example, when there is a downward movement on the demand curve, the price will decrease from P1 to P2, the quantity demanded will increase from Q1 to Q2. The reason that causes movement along the demand curve will be a change in price, quantity, and so on.

沿着需求曲线的运动会引起价格和需求量的变化。例如，当需求曲线向下移动时，价格将从 P1 下降到 P2，需求量将从 Q1 增加到 Q2。导致需求曲线移动的原因是价格、数量等的变化。

The shift in the demand curve
需求曲线的移动

A shift in the demand curve will only cause the change in the quantity demanded but not affect the price of the product or services. For example, when people expect printing paper to be expensive in the future, they would buy more now and cause the demand curve to shift to the right. The reason for the shift in the demand curve is seasoning, the expectation of the price, income level, and so on.

需求曲线的移动只会引起需求量的变化，而不会影响产品或服务的价格。例如，当人们预计未来打印纸会很贵时，他们会立即购买更多，从而导致需求曲线向右移动。需求曲线移动的原因是调味、价格预期、收入水平等。