Complete the second sentence so that is has similar meaning to the first sentence: How long have you been an ethologist?

Complete the second sentence so that is has similar meaning to the first sentence .
1. How long have you been an ethologist ?
When ............................................................
2. Who di these beatiful ornaments belong to ?
Whose...........................................................
3. What is the price of a dish of five - coloured sticky rice?
How much...............................................................