1. You don't have to unplug the electric cord to the pressure cooker. You can see the light of preserving temperature on the cooker. If you unplug the electric cord, the cooked rice in the cooker will be spoiled with ease. (Is this passage correct? Would you correct the wrong expressions?)

2. Let's prepare for going out.
3. Let's prepare going out.
4. Let's prepare to go out.
(From 2 to 4: Which expession is right?)

5. By making a wish, you throw a stone on the surface of the water. However, in our country, we don't have such a custom. (Is this passage correct?)

1 answer

1. You don't have to unplug the electric cord to the pressure cooker. You can see the light of preserving temperature on the cooker. If you unplug the electric cord, the cooked rice in the cooker will be spoiled with ease. (Is this passage correct? Would you correct the wrong expressions?)
What is "preserving temperature"? In the second sentence, the repetition of cooked/cooker is awkward; delete "cooked" and keep "cooker." I'm not sure what you mean by "with ease."

2. Let's prepare for going out.
3. Let's prepare going out.
4. Let's prepare to go out.
(From 2 to 4: Which expession is right?)
#4 is correct; the others aren't.

5. To make a wish, you throw a stone into the water. However, in our country, we don't have such a custom. (Is this passage correct?)