We have to the picnic because of the heavy rain.A. spend onB. put offC. put onD. look up

问题补充：

We have to the picnic because of the heavy rain.

A. spend on

B. put off

C. put on

D. look up

答案：

A. spend on

(答案→)B. put off

C. put on

D. look up

解析：短语辨析。Spend…on…把…花在..之上；put…off推迟；put on增加，上演；look up查找；句意：因为大雨，我们不得不推迟野餐。根据句意说明B正确。