1 . It may seem like building castles in the air, but given the rate at which artificial intelligence, or AI, is being developed, in the future such dreams may actually come true.

A．having plans or dreams that are not likely to happen or come true

B．building airports with good condition

C．making a large strong building with thick high walls and towers

2 . ________ covered the ground like red autumn leaves, but no wind would blow them away.

A．Wells

B．Bricks

C．Traps

D．Walls

E．Cracks

3 . He is never satisfied with what he has got. The grass is always greener on the other side of the ____.

A．road

B．fence

C．wall

D．garden

4 . The newly-built house, _______ are painted light green, is really a peaceful place for us, especially after hard work.

A．the wall of which

B．whose walls

C．of which walls

D．the walls of that