We’ll have a picnic in the Summer Palace this Sunday ________it rains or it’s very cold.

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

We’ll have a picnic in the Summer Palace this Sunday ________it rains or it’s very cold.

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

We’ll have a picnic in the Summer Palace this Sunday       it rains or it’s very cold.

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

We’ll have a picnic in the Summer Palace this Sunday ________it rains or it’s very cold.