Now listen to the following recording and answer questions 16 to 18.
16
A.To create a relief printing surface.
B.To create the typeset, namely the hot metal typeset.
C.To inject a molten metal alloy into a matrix.
D.To mix metals to create a new metal.
17
A.It dominates the printing industry for the 18th century.
B.It is much slower than the Gutenburg-style system.
C.Its operators have to place down one letter at a time.
D.It revolutionizes newspaper publishing.
18
A.It must be done with tools.
B.It can be a difficult and skillful task.
C.It doesn't need much skill.
D.It is easy but needs much patience.