What do you know about Nigeria?At a rough estimate,it is thr

What do you know about Nigeria?At a rough estimate,it is thr 请问"at a rough estimate"是什么意思? I do not know what I can do about it.I am completely at a lo do you know what--------(it)name is Do you know（ A.what color is it B.what can he do C.where is What do you know about me at last What else do you know about it?改同义句 应该是Do you know what is it 还是Do you know what it is Do you know what it is?还是Do you know what is it? Do you know what time it is at the m______ in London? Do you know what time it is 还是is it? what time do you get up?____A it is six.B About six.C.At six