How do I prevent making the converse error?

That seems to be my main issue of concern....

Gregory,

In order to avoid making the converse error, you'll want to do two things:

1. Each time you read a conditional statement, think about how each element of the conditional relates to the other.
If you see that statement "steam is created whenever I heat a pot of water," think about which part of the statement will go before the arrow of the diagram, and which part will come after. If you do this each time you see a conditional statement, you'll start to be able to spot "if/then", "if and only if", "always", etc. statements from a mile away, and you'll know exactly what to do with them.

2. Practice diagramming.
This is really important. You've got to expose yourself to conditional statements, and you've got to practice diagramming them out. The Exercise Sets will give you some practice with conditionals. And you can get additional practice by completing Question Sets that have the word "Conditionals" in the title/description. If, when you're practicing, you find that you're flipping conditionals around (committing the converse error), post a comment. We'll try to give you some tips based on your specific errors.

The key to mastering conditionals is practice. Can't stress that enough.

This question should say that freaks always come out at night. All it says is that they do come out at night. Without stipulating that they only or always come out at night, their presence is no real indicator of time of day.