. It rained heavily in the south. _______serious flooding in several provinces.

A．caused

B．having caused

C．causing

D．to cause

¹⁹⁸Au胶体进行骨髓显像时的常用剂量为（）。

A.3.7MBq

B.37MBq

C.37～148MBq

D.370～740MBq

E.740MBq