______ is known to all, the earth travels round the sun once every year．

______ is known to all, the earth travels round the sun once every year．

1. A.
   That
2. B.
   As
3. C.
   What
4. D.
   It

______ is known to all, the earth travels round the sun once every year．

       A．That       B．As         C．What      D．It

______ is known to all, the earth travels round the sun once every year．

______ is known to all, the earth travels round the sun once every year．

　 A．That　 B．As　 　 C．What　 D．It