Study the following examples
1. Francisco gets a shopping cart. Then Mrs. Garcia reads the shopping list
(Two simple sentences) وهذا هو الجواب
2. Francisco gets a shopping cart, and then Mrs. Garcia reads the shopping list
(Compound sentence) وهذا هو الجواب
3. Francisco gets a shopping cart before Mrs. Garcia reads the shopping list
(Complex sentence) وهذا هو الجواب

It started to rain. Ahmad put on his raincoat

2simple sentences وهذا هو الجواب
It started to rain, so Ahmad put on his raincoat

Compound sentence وهذا هو الجواب
Because it started to rain, Ahmad put on his raincoat

Compound sentence وهذا هو الجواب