Audio not working in certain parts of iMovie

Today we had a student who was working in iMovie and while inserting audio clips into the project, no sound from those clips would be projected but only at certain parts in the movie. Most likely the cause for this is that there is another audio clip that is corrupt or damaged in some way that is preventing that audio clip from working. To check/fix this problem:

• Click on the waveform button
• 
• All of your audio clips should load and you should be able to see the various sound levels from each of your clips
• Look for any clips that have a loading circle that just doesn't seem to go away (also check for clips that have a yellow triangle with an exclamation point in them)
• If you find any of these clips, simply delete that clip and the rest of your audio should work.