公司采购材料一批，货款未付，此项业务会使（）。

A.资产和权益双方同时等额增加

B.资产和权益双方同时等额减少

C.资产内部有增有减，增加和减少的金额相等

D.资产和负债双方同时等额增加

We have just heard a warning on the radio ________ an earthquake is likely to strike that area again.

A．which

B．what

C．that

D．when