1 Last week, we visited a large factory where they make window glass. ______ Special rollers too

1Last week, we visited a large factory where they make window glass.

______ Special rollers took hold of the sheet at either side and carried it upwards.

______ Here some men lowered a metal frame into the liquid.

______ They then fed the mixture into a big hot oven.

______ Our guide told us that at this stage it was necessary for the glass to cool slowly as this would make it very strong.

______ At a height of 30 feet, the sheet of the glass became cool and another machine cut it into big pieces which workmen stored away together.

______ Then they added some broken glass to the mixture as this helps it to melt.

______ We first saw workmen mixing sands and other materials together in the right amounts.

______ At the far end of the oven, a stream of liquid glass came out.

______ As the frame came up, it pulled away a hot sheet of glass.

11Finally the glass was ready for use.