Why must we use "so that" in the first sentence and "so" in the second one?
- Let me know when you are going to send it so (that) I can make the payment.
- I've bought some fruits so you don't need to go to the grocery when you arrive.
I don't understand the difference between the use of so and so that in these sentences.
Both can answer to the question "why".
- Why must you let know when you are going to send it? To make the payment.
- Why have I bought some fruits? To avoid going to the grocery to you.
I've bought some fruits in the intent of avoiding to go to the grocery in this sentence: not going to the grocery is not a result, but the purpose of buying some fruits for me, but I know I'm wrong.
The difference for me is not clear.
