圈梁的作用是箍住楼板、贯穿墙身，增加建筑物整体性，防止建筑物不均匀沉降，抵抗地震和其他振动对建筑物的不良影响。( )
参考答案：对
Bob can't come out to play because he help Dad in the garden. [ ]
A. can
B. can't
C. has to
D. must
论述结合《从邮局看变化》，谈谈其对比式的写作特点。
