Three years _____ a short time. You have to study hard. [ ]
A. is
B. are
C. be
D. were
答案:A
外用内服均能收敛止血的药物是()。
A.白矾
B.雄黄
C.降香
D.蜂房
E.硫黄
CRH2型动车组车厢天花板高度为()。
A.2277mm
B.2278mm
C.2279mm
D.2280mm