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下列哪些選項(xiàng)是國(guó)際學(xué)術(shù)會(huì)議的開場(chǎng)語句?()

A.I am very pleased to have this opportunity to....
B.First let me express my gratitude 
C.Now after a short introduction I would like to read to the main part of my paper...
D.The last part of my report will be devoted to....

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