Two sentences, which is right? (After the Second World War, Australia began...)

[Vaok]

would anybody help me ?

After the Second World War, Australia began to transform itself into the modern country it is today．

After the Second World War, Australia began to transform itself into the modern country as it is today.

can "as" be omitted in the first sentence? why?

[Mister Micawber]

The 'as' is wrong; the first sentence is right. It is an optionally omitted 'that', not 'as':

After the Second World War, Australia began to transform itself into the modern country (that) it is today．
.
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Native English teacher at Mister Micawber's