下列有关蛋白质变性的叙述，哪项是错误的（）

A.蛋白质变性时其理化性质发生变化

B.蛋白质变性时其一级结构不受影响

C.蛋白质变性时其生物学活性降低或丧失

D.去除变性因素后变性蛋白质都可以复原

E.球蛋白变性后其水溶性降低

Until recently historians assumed that calendars ________ with the advent of agriculture.[ ]

A. came to existence

B. came to exist

C. were existed

D. were existential