029. How often...?
多久有一次……?

[句型解析]
如果要问航班，汽车多久来一趟等，则要用“How often...?”表示频率。

[实例]
1. A: How often is there a leap year?
几年有一次闰年?
B: Every fourth year.
每四年。
2. How often is there a flight to Shanghai?
多久有一次到上海的航班？
3. How often do you write to your parents?
你多久给父母写一次信？

[实战练习]
A: I’ve been having bad dreams lately.
我最近经常做恶梦。
B: Really? How often?
是吗？多频繁啊？
A: Just about every night.
几乎每晚。
B: What do you dream about?
你梦些什么？
A: I dream about being in a boat and suddenly a storm comes and I drown because I can’t swim.
我梦见在一只小船里，突然来了一阵风暴，我给淹死了，因为我不会游泳。
B: Maybe you should learn how to swim. Then you won’t have any nightmares.
可能你该学学游泳，那你就不会再做恶梦了。