in demand和 on demand
问题描述：
in demand和 on demand
答
in demand 很热手,很受欢迎,炙手可热The new Audi is very much in demand in China 新的奥迪轿车在中国很热手on demand 在要求时,一经请求 When you buy for cash you must pay on demand 现款交易需要见货即付...