assume的用法后面是否要加虚拟语气

vt.
1.以为;假定为;(想当然地)认为[+(that)][O2][O8][O9]
I assumed that he had gone for a stroll.
我想他去散步了.
2.承担;就任;取得
The prince assumed power when he was only fifteen.
王子在十五岁时就掌权了.
3.呈现;采取;采用
His illness assumed a very grave character.
他的病显得非常的严重.
4.把...视为己有,僭取,夺取
5.装出,假装
He assumed a look of surprise.
他装出吃惊的神色.