When did she begin learning English?
⇒ How long is it since she learnt English?
Cấu trúc tương đương:
When + did + S + begin/start + V-ing/to V?
How long is it since + S + V(past)?
It took Ginger 90 minutes to see that movie on TV.
⇒ Ginger spent 90 minutes seeing that movie on TV.
Cấu trúc tương đương:
It + takes + S + time + to V = S + spend + time + V-ing.
(Ai mất bao lâu làm gì) (Ai dành bao lâu làm gì)