21．The Great Wall winds its way from west to east，________deserts，________mountains，________valleys，till at last it reaches the sea.
A．over；across；across
B．through；past；past
C．across；over；through
D．past；through；over
22．Roses need special care________they can live through winter.
A．because B．so that
C．even if D．as
23．—What happened to you the other day?
—I________to Beijing，but I missed my flight.
A．would fly B．was flying
C．had flown D．flew
24．Under a big tree________，half asleep.
A．did sat a fat man B．a fat man sat
C．did a fat man sat D．sat a fat man
25．If I were________younger I would do________I am interested in.
A．some；what B．any；what
C．some；whatever D．any；whatever
26．We often provide our children with toys，footballs or basketballs，________that all children like these things.
A．thinking B．think
C．to think D．thought
