1. came reading I when was a book home my parents.
I was reading a book when my parents came home.
Составим предложение из слов. Подлежащее - I, сказуемое - came. После when стоит подлежащее, потом сказуемое.
2. the kitchen was Dad when opened we the front door in cooking.
Составим предложение из слов. Подлежащее - Dad, сказуемое - was cooking, then когда? when we opened the kitchen door.
Ответ:
<ol> <li>I was reading when my parents came home.</li> <li>Dad was cooking in the kitchen when we opened the front door.</li> </ol>