\cline{i-j}
The \cline
command draws horizontal lines across the columns
specified, beginning in column i and ending in column j, which are
identified in the mandatory argument.
It is used in the tabular and
array environment.
Two (or more) successive \cline
commands draw lines in the same
vertical position. Typically, \cline
commands are placed after a
\\
(line breadk) command so that
they separate items on two lines; they do
not, however, need a line break command afterwards.