- How does Mrs. Green usually go to work?

- She _____ take a bus, but now she _______ riding a bike because she wants to lose weight.[ ]

A. used to; used to    

B. was used to; is used to    

C. used to; is used to    

D. is used to; used to

以下哪个加温系统由左主起落架的空地电门控制？

A、空速管加温和AOA传感器加温

B、结冰探测器和AOA传感器加温

C、机身防冰系统泵

D、风挡防冰系统