Large quantities of water, as well as some other timely help including a medical team ___since the serious drought hit Yunnan Province.

A．has offered

B．had been offered

C．have been offered

D．is offered

下列（）属于最重要的土壤吸收性能类型

A.机械吸收

B.物理吸收

C.化学吸收

D.离子交换吸收