In the English Grammar Profile, B1 point 50 in the category of CLAUSES is defined as:
combine clauses of the same type, main or subordinate, finite or non-finite, with conjunctions.
*This is difficult to interpret exactly because at A1, students can omit the subject after ‘and’ or ‘or’. We can start by looking at the structure of the EGP examples:
- You will have a great time with your friends because I know they are going to the seaside and staying in a hotel near the sea.
- They chose our school because it’s very modern and there are a lot of students.
- Otherwise, if you want to relax and see your friend, the countryside will be the best.
- You asked for my advice about either going on holiday with your parents or staying with your friends.
The examples seem to suggest there should be other conjunctions in the sentence too, such as, ‘because’, ‘if’ or ‘either’.
Here is an expert example: