______byguardswithgunstheyraisedtheirlegsinunisona

______by guards with guns，they raised their legs in unison and made their way to the edge of the highway，Interstate 65.

A. Watching over

B. Watch on

C. Watched over

D. Be watched over

正确答案：C
[解析]65号州际公路被持抢的警卫们守卫着他们迈着整齐的步调走在高速路边用被动语态故选C