请教英语大师：找出下列句子中错误或遗漏的单词,每句有一个错误或遗漏之处

请教英语大师：找出下列句子中错误或遗漏的单词,每句有一个错误或遗漏之处
 How long have you pulled the plug from a sink and watched the water go
 down the plughole?Probably many times!Whether you do this in Hong  
Kong,you saw that the water swirls anti-clockwise.But do you know why?

Find in this interview with Dr Xi.
How does water swirl anti-clockwise when going down the plughole?
The way water goes down a plughole has to do with earth's rotation.It's
called the‘Coriolis Effect’.If you be in the northern hemisphere,the water
swirls anti-clockwise.It swirls in the opposite direction you are in the southern hemisphere.
What does water behave directly on the equator?
That's an interesting question.If you tried this experiment directly on the
equator,the water swirls in neither direction.Therefore,as you put a 
matchstick in the water,it spin at all.
How quickly do you need to move away from the equator before the water starts spining?
About twenty metre.
How much other things are affected by the Coriolis Effect?
There quite a few-for example,ocean currents and wind directions.Like
water swirling down a plughole,the winds of a typhoon blow clockwise
anti-clockwise,depending on which hemisphere a typhoon is located in.

这是篇短文，每句有一个错误或遗漏之处。

how long 改成 how often
whether改成if
saw改成will see
does改成could
has后面加something
be改成are
you are前面加if
what改成how
tried改成try
spin前面加doesn't
quickly改成far
metre改成metres
much改成many
there后面加are
clockwise和anticlockwise中间加or
a typhoon改成the typhoon

再问： 谢谢！请问”Find in this interview with Dr Xi.“和”equator,the water swirls in neither direction.Therefore,as you put a “这两行里哪里有错？ 麻烦您帮忙
再答： How does water swirl anti-clockwise when going down the plughole?这一行那个how改成why，刚才疏忽了。 Find in this interview with Dr Xi.实在要改的话，就把with改成of吧。 equator,the water swirls in neither direction.Therefore,as you put a这个没错误，因为后面的那个spin前面少了doesn't，一个句子不是只有一个错误的嘛？
再问： 谢谢！是一行就有一个错误或遗漏！