Such as: Countries(, ) such as Brazil and Canada are large

[Tung Quoc]

Please read:

1.Countries such as Brazil and Canada are large.
2.Countries, such as Brazil and Canada, are large.
3.Such countries, as Brazil and Canada, are large.
4.Such countries as Brazil and Canada are large.

a.I think only (2) is incorrect. Is it right?
b.Can I remove such as Brazil and Canada in (2) and as Brazil and Canada in (3)?Please tell me the rule?
c.What is the difference in meaning btw (1),(3) and (4)?Are they the same meaning?

Quoc

[DOlier]

[Yankee]

[Tung Quoc]

Dear teacher,

That means I can remove as Brazil and Canada in (3) without significantly changing the meaning. Is it right?

Quoc

[Yankee]

[Tung Quoc]

Dear teachers,

In your opinions, (1) and (2) have the same meaning. So, do you think it's necessary to put ",.....," in (2)?
,..., is redundant?
Quoc