New type of shell roof board has rational structure, but its design calculation was very complicated.

新型薄壳屋盖的结构合理，但它的设计计算工作量很大。

youdao

New type of shell roof board has rational structure, but its design calculation was very complicated.

新型薄壳屋盖的结构合理，但它的设计计算工作量很大。

youdao