Every possible means ________, but the teacher as well as the students ________ found a solution to the problem yet.

A．has been tried; hasn’t

B．has tried; haven’t

C．have tried; haven’t

D．have been tried; hasn’t

下列体征属损伤后的危急证候是（）。

A.神志昏迷

B.神昏谵语

C.汗出如油

D.瞳孔缩小

E.呼吸微弱