Unless/Even if/In case

How do I use \"unless\"?
Unless has the same meaning as if not. Compare the following:
I will buy a house if I'm rich.
I will buy a house unless I'm poor.
Therefore,
if it rains = unless it doesn't rain
if it doesn't rain = unless it rains
How do I use \"even if\"?
Even if is used to emphasize or stress an if statement. It should express some surprise. For example:
I wouldn't buy a home if I had enough money. or (if you want to stress the situation)
I wouldn't buy a home even if I had enough money.
How do I use \"in case\"?
You should use in case if there are instructions or commands being given in the result clause. In case introduces something that probably won't happen but that might. Remember the structure:
In case + <if clause>, <result clause>. or
<result clause> + In case + <if clause>.
For example:
In case it rains, take the umbrella with you. (It is probably not going to rain but it might.) or
Take the umbrella with you in case it rains. (It is probably not going to rain but it might