Luggage
bags, cases, etc. that contain somebodys clothes and things when they are traveling 行李 [主要用于英国英语中]
1. Never leave your luggage unguarded.
千万注意看好自己的行李。
2. Please help me with this luggage.
请帮我搬一下这件行李。
3. This luggage is too heavy for me to lift.
这件行李太重，我提不起来。
Baggage
bags, cases, etc. that contain somebodys clothes and things when they are traveling 行李 [主要用于美国英语中]
1. The baggage is two kilos overweight.
那行李超重两公斤。
2. Could you give me a hand with the baggage?
你能帮我拿一下行李吗？
3. We loaded our baggage into the car.
我们把行李装上了车。
【注意】
1. luggage多用于英国英语中，而baggage多用于美国英语中。
2. luggage和baggage都是不可数名词。