— Have you seen my e-mail about our TESL project?  

— Yes. Luckily I checked my e-mails yesterday. Normally I ______ my e-mail box for days.[ ]

A. haven't opened  

B. didn't open   

C. hadn't opened      

D. don't open

汽机一、二级旁路的降温降压范围各是多少？