___________ caused the accident is still a complete mystery.

下列句子中加点的词语与“吾妻死之年所手植也”中的“手”的用法相同的一项是

Have you ________?—No. I had the wrong number.

How long have you__________ the book –For three days.

Excuse me, is the book shop far from here?—No, it is just _________ of our college