3．We can infer
from this passage ______.
A．we should
learn many different languages
B．Captain Cook
made a mistake in understanding
C．Captain Cook
was a foolish explorer
D．the
importance of a language in common
B
There are two types of twins; identical and non-identical twins.
Identical twins are formed from a single egg in mother’s body which divides to
from two separate babies. Identical twins look the same, and are often dressed
by their parents in clothes of the same colors. It is often difficult to tell
identical twins from each other, even when they are standing side by side.
Non-identical twins come into being when the mother produces two separated eggs
a the same time, both of which grow to form babies. In this case the twins look
like normal brothers and sisters and are easy to tell one from the other.
In the 1970s and 1980s a scientist did some research into twins. He
invited many pairs of identical twins to university and asked them to take part
in a week of tests. He was particularly interested in adopted (收养) twins who had been separated at
birth. He would give the twins different kinds of tests to study their speed of
thinking, their speech, their memory, the ways they saw and heard different
things, and so on. Time and time again he found separated twins who preferred
clothes of the same color, used the same kind of shaving soap, wore the same
shaped square glasses and the same colored socks.
There is a third type of twins, but it is a very unusual one. Twins
which are joined together at birth are known in western countries as Siamese
twins.