title: Put tick labels of only x-axis inside plotting area
body: <p>Is it possible to put tick labels of only x-axis inside plotting area?
  I am trying:</p>
  
  <pre><code>axis(1,at=c(0:71),c(rep(0:23,3)),cex.axis=.7, font=1,tck=.01)
  </code></pre>
  
  <p>It seems that:</p>
  
  <pre><code>par(mgp=c(0,-1.4, 0)) 
  </code></pre>
  
  <p>puts both <code>x</code> and <code>y</code> tick labels inside plotting area. </p>