根據題意,後面應該加to do。例如這一個句子,我的媽媽花了30分鐘時間做飯。My mother takes  30 minutes to cook the delicious food.
是加to do 構成 it takes sb some time to do sth 幹某事花去某人多少時間
其中的 it 是形式主語, to do ,sth是真正主語,這樣避免頭重腳輕,達到句子平衡
例如 : it took me two hours to drive from my home to school. 開車從家裏到學校我要用二個鐘
這種句子結構還有
it is adj /n. to do sth
例如: it is polite to wait in line
排隊等候是有禮貌的
It takes sb. + 時間段 + to do.反過來,Doing sth. takes sb. + 時間段.
常用的是:take sb some time to do sth:(某事)花某人時間去做,如:It takes me ten minutes to walk to school every day.而take one's time 常用於口語中,表示,如:--- I'll get my bag.--- Take your time.I'll be waiting for your at the gate.