<p>EE 20 is the prerequisite for EE 120 and 126. One or both of these in turn is a prerequisite for EE 121, 123, C125, and 129. If these courses are of interest to you, you should take EE 20 as soon as you can.</p>
<p>CS 70 is a prerequisite for CS 161, 162, 169, 170 (and 172, 174, 176 through 170), 188, and 189. However, all except CS 188 and 189 list CS 61B or 61C as a prerequisite in addition, so there is less advantage to taking CS 70 in the fall than in the spring, since you will not get to CS 61B until the spring anyway.</p>