73.As suggested by the text, how can glass be
made less brittle?
A.It can be heated and then
cooled quickly.
B.It can be cooled and then
heated slowly.
C.It can be heated and then
cooled slowly.
D.It can be cooled and then
heated quickly.
92D
The basenji is a central African
hunting dog. It comes from a country called Chad,
which is north of the Central
African Republic. The basenji was well-known
as the "silent dog" because for centuries no basenjis had ever been
known to bark (吠). Then at a dog show in London in 1953, a basenji
actually barked.
As well as being clever,basenjis
are known for their natural courage and are still popular hunting dogs in Africa. But in America people keep them mainly
because they are gentle and full of fun. The basenji has an unusual habit:it
washes itself all over like a cat. It is a middle-sized dog, 16 or 17 inches
high from the shoulder. It weighs about 20 pounds. A basenji's coat is short
and silky.It may be brown, white, or gold ,or a mixture of these three colours.