寒战，间歇热后体温升高，四肢厥冷，白细胞计数不高或减少，血培养阳性（）

A.革兰阳性细菌败血症

B.革兰阴性细菌败血症

C.菌血症

D.脓血症

E.毒血症

-I haven't been to the Great Wall.    

-If you have an opportunity ________ there, you must take it.     [ ]

A. to go

B. to going

C. going

D. go