在特殊情况下,锚段长度小于()时,可以不设中心锚结。
A、500m
B、600m
C、800m
D、1000m
参考答案:C
若{an}是等差数列,且a1+a4+a7=45,a2+a5+a8=39,则a3+a6+a9=[ ]
A.39
B.20
C.19.5
D.33
_____the danger from enemy action, people had to deal with a severe shortage of food, clothing, fuel, and almost everything. [ ]
A. As soon as
B. As long as
C. As far as
D. As well as