Надо используя косвенные вопросы тоесть в более вежливой форме составить предложения они должны начинаться с do you know ..пример why did ancient people leave do you know why ancient people leave. обратите внимание на did я не знаю что с ним делать вот сами предложения 1. where is he 2 when did you see the explosion 3 why did it disappear 4 what have the scientists found in the sea
2. Do you know when did you see the explosion?
3. Do you know why did it disappear?
4. Do you know what have the scientists found in the river?
Did используется в Past Simple
2. Do you know when you saw the explosion?
3. Do you know why it disappeared?
4. Do you know what the scientists have found in the sea?