C. We use in case to talk about things we should do in order to be prepared for possible future situations. (e.g. Shall I keep some chicken salad for your brother in case he’s hungry when he gets here?)
a. Do not use ‘will’ after in case, but use a present tense for the future. (e.g. I’ll leave my phone switched on in case Dul calls. (not in case Dul will call))
b. We don’t use in case to mean ‘if’. (e.g. Let’s take our swimming costumes in case there’s a pool at the hotel. = We don’t know if there is a pool there. Let’s take our swimming costumes if there’s a pool in the hotel. = We will wait until we know about the pool before we decide.)
c. can use in case + past to say why somebody did something. (e.g. I left my phone switched on in case Dul called. (= because it was possible that Dul would call))
d. In case of is not the same as in case. In case of ~ = if there is ~ (especially on notices etc.) (e.g. In case of breakdown, please press the alarm button and call this number. (if and when the lift breaks down, ~))