Only when our country has aircraft carriers (航空母舰), our distant islands more effectively.
A. we can guard
B. can we guard
C. we guard
D. do we guard
网友回答
A. we can guard
(答案→)B. can we guard
C. we guard
D. do we guard
解析：考查only引导的的部分倒装句。Only引导的倒装句必须满足两个条件，only必须放在句首，必须强调状语。本题满足这两个条件，所以选择B。