The key advantages of fuel cells include raising the __________________ and reducing air pollution.

A．New foods to try when traveling.
B．Making reservations for the best travel.
C．Avoiding gaining weight while traveling.
D．Adjusting to time changes when traveling.

A．She had moved out of the old address.
B．She ignored it.
C．The library didn’t try to inform her about it.
D．The landlord refused to give the books back to her.