1: David doesn't want to get old
Mr Wilson doesn't know where the clock takes them (я бы написал him)
The Time Travel clock doesn't like Mr Wilson and the children
2: Hippos don't live in the sea. They live in Africa.
Milk doesn't come from plants. It comes from cows.
Potatoes don't grow on trees. They grow underground.
The Sun doesn't go around the Earth. The Earth goes around the Sun.