为什么会出现这种现象用英语怎么说

1、Why does this happen?

2、How could this be?

3、How can it be?

4、how did we come to this?

为什么：why; why is it that; how is it that; forwhy; whereto

出现：appear; appearance; arise; emerge; grow

现象：phenomenon; appearance

例句：

1、为什么会出现这种现象呢？在大量的实验中，我们发现各种材料中均有价电子密度以及正电子寿命饱和的现象，但目前还没有人深入研究这种现象的本质。

Over a very large number of experiments, we found that the phenomenon of covalence density and positron life saturation are almost existed in all kinds of materials, but there is still no one in-depth study on the nature of this phenomenon. 

2、为什么会出现上述这种相反的现象呢？

Why does this reverse phenomenon appear? 

Why did it have to happen?How could this be?How can it be?这三个都可以

why did it happen?
how did we come to this?
why did this situation occur?

why
did
it
have
to
happen?
How
could
this
be?
How
can
it
be?
这三个都可以

Why will appear this kind of phenomenon？

Why does this phenomenon arise?

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