design to be可以跟做表语的成分,design as只能跟做宾语的成分,跟名词结构的时候,可以相同。the chair designs to be comfortable. 不能用as. 但是design…as一般用作design sth as或者被动be designed as. they design the book as safety handbook.
追问那The book is designed to be a safety handbook和The book is designed as a safety handbook一样吗?