A.铁
B.冰
C.玻璃
D.沥青
AB
– I prefer _________shopping to _________at home.
A.to go; staying
B.going; stay
C.going; staying
D.go; to stay
补强圈补强是按等面积补强原理设计的,即所增加的截面积只要大于或等于开孔所减少的截面积就能满足补强要求。