视事 meaning in English

(of officials) attend to business after assuming office; assume office

If the president can no longer serve , who becomes president
如果总统不能视事,谁会变成总统
The president normally reports to his desk before 8 a . m
总统通常在早上8点钟前到办公室视事。
If both the president and the vice president can no longer serve , who becomes president
如果总统、副总统都不能视事,由谁来作总统
Who becomes president if both the president and the vice president can no longer serve
问：如果总统，副总统都不能视事，由谁来做总统？