_ on roofs and telegraph wires.These birds are swallows.They are __62__ together because, very soon, they will be flying __63__ to much warmer lands, where they will find __64__ the small flying insects on which they __65__.There are no such insects __66__ in Britain during the winter; it is __67__ cold for them.
The swallows settle, fly off, swoop, and __68__ again.this they do many times, for they are making short __69__ flights in order to be fit for the long journey __70__ them.
__71__ of these migrating birds leave Britain in the autumn.They fly __72__ for hundreds of miles __73__ they reach the warm lands of Africa.But not all the birds get there, for many of them perish in the stormy weather they meet with __74__.
In the spring of the following year they __75__ the long and tiring journey back to Britain.They return to the identical barn or tree in the __76__ district which they had left the __77__ autumn.How do these birds find their__78__ there and back over such vast distances？ Nobody knows exactly __79__, but it has something to do __80__ winds and air currents.
61.a.being perched b.perched c.being perching d.be perched
62.a.gathering b.assembling c.waiting d.forming
63.a.to south b.the south c.to southwards d.south
64.a.a great number of b.a great deal of c.plenty of d.numerous
65.a.feed b.are fed c.eat d.rely
66.a.near b.about c.nearby d.over
67.a.too b.a bit c.very d.much
68.a.fly off b.swoop c.settle d.turn back
69.a.practical b.practicing c.practice d.practiced
70.a.in advance b.ahead of c.in front of d.in front
71.a.Swarms b.Herds c.Flocks d.Schools
72.a.firmly b.stoutly c.harshly d.steadily
73.a.until b.before c.when d.as
74.a.in the way b.on the way c.half the way d.all the way
75.a.take b.fly c.find d.make
76.a.old b.original c.familiar d.identical
77.a.before b.previous c.above going d.former
78.a.way b.path c.course d.route
79.a.why b.when c.how d.what
80.a.against b.away c.for d.with