how often,how long,how soon与how far这四个疑问短语都以how开头，但用法各不同。
例如：
How often do you play basketball？
你多久打一次篮球？
How long have you been waiting here？
你在这儿等多长时间了？
How long is this river？
这条河有多长？
How soon will you get there？
你多久能到那儿？
How far is it from here to the zoo？
这里离动物园有多远？
Let's have a try.
谢谢！
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