在一定条件下，下列的物质问的转化能一步实现是①Fe→Fe₃O₄    ②S→SO₃    ③CuSO₄→Cu    ④Na₂CO₃→NaC1（　　）

A．①②③

B．①②④

C．①③④

D．②③④

The pictures of the Loch Ness Monster show a remarkable resemblance to a plesiosaur, a large water reptile of the Mesozoic era presuming extinct for more than 70 million years.

A．supposed

B．presumably

C．presumptuous

D．is presumed