．Millions of pounds' worth of damage___________by a storm which swept across the southeast of China last month.

A．has been caused

B．had been caused

C．will be caused

D．will have been caused

钛管焊接所用的氩气的纯度直接影响焊接质量，要求含氩量应不小于______。

A．95.5%

B．85.5%

C．90.5%

D．99.5%