expedia 上定的时候看到是两件，订完之后，收到的邮件没有写行李数，在国航官网看到的免费的是一件：
　
(i) Economy Class passengers travelling on the following routes may check in one item of baggage for free weighing up to 23 kg (50 lb):
Air China-operated routes to Europe, Africa, the Middle East (excluding the UAE), Asia-Pacific (excluding Japan, Kazakhstan, Australia and New Zealand), Hong Kong, Macau, Taiwan and Hawaii.
(ii) Economy Class passengers travelling on the following routes may check in two items of baggage for free, each weighing up to 23 kg (50 lb):
Air China-operated routes to the Americas (excluding Hawaii), Japan, the UAE, Kazakhstan, Australia and New Zealand.