something，enjoy，difficult，difference，out
There are many 76
kinds of trains in the world．There are fast trains
and slow trains．There are trains under the ground and
trains over the water．
In big cities，the streets are usually busy．So you can find
subways under the ground．They carry people in
and 77 of the city．
Can a train run
over the water? Yes，it can．There are bridges over the river．The trains can easily go over the water．But it’s 78 to
build the bridges．
Today trains have dining―rooms for
people．You may buy 79 to eat in them on the way if you
are hungry．
Trains are important for children，too。They have model（模型）trains．With the model trains they can 80 the beautiful world of trains．
