is used when taking precaution against a possible threat/danger, to avoid an unwanted situation.
Do something in case something happens.
Set up your alarm clock in case we fall asleep.
Wear your helmet in case you fall.
Bring your bathing suit in case we go swimming.
a. We'll take some food in case we get hungry on the road.
b. Loren will draw a plan for him in case they can't find her house.
c. Take an umbrella with you in case it rains.
d. I don't want to go out in case my friend calls.
e. Sally will write down the number in case she forgets it.
f. Take your migraine pills with you in case you get headache later.
Do not use will after in case.
I will cook now in case he comes home early.
I will cook now in case
he will come
You can also use in case to say why someone did something in the past.
Matilda took her raincoat with her in case it rained.
Hans bought some wine on the way home in case his wife wanted some.
1. We had better hurry, we'll miss the last train.
We had better hurry in case we miss the last train.
2. Ted had better come home early. The visitors will come today.
Ted had better come home early in case the visitors come today.
3. You had better close the windows. It may rain heavily.
You'd better close the windows in case it rains heavily.
4. Mr. Park telephoned home. His wife wanted something.
Mr. Park telephoned home in case his wife wanted something.