Oversea property capital gains tax

[Xiaoyu Huang]

I read online that if you buy another investment property in half year after you sell the first investment property, you don't have to pay capital gains tax, anybody know if it's the same to sell an oversea investment property and buy another one in America? What if the first oversea apt didn't rent out, not a investment property, i sell it then buy a investment apt in America, do I need to pay capital gains tax?