— May! How is your plan? I heard you started it last Sunday.

— Oh! I _____ for it, but I haven't decided where to start it. [      ]

A. have prepared

B. had prepared

C. have been preparing

D. was preparing

一氧化碳中毒时，血中明显增多的血红蛋白是（）

A.碳氧血红蛋白

B.高铁血红蛋白

C.氧合血红蛋白

D.硫化血红蛋白

E.还原血红蛋白