We’ll visit Expo 2010 Shanghai this Sunday_______ it rains or it’s very hot．

1. A.
   since
2. B.
   if
3. C.
   unless
4. D.
   until

We’ll visit Expo 2010 Shanghai this Sunday_______ it rains or it’s very hot．

A．since                B．if             C．unless          D．until

We’ll visit Expo 2010 Shanghai this Sunday_______ it rains or it’s very hot．