说某物昂贵常用expensive, 说某物便宜常用cheap.例如：
①The schoolbag is expensive/cheap.
说或者比较某物价格高低用high/low.例如：
①The price of this kind of rice is higher than that one.
②Compared with the goods in that store, the price of these ones are much lower.
③The price of this jewellery is too high for me to buy it.
