The key answer of exercise 2

a) -

b)

1. So, Therefore
2. since, as
3. because, since
4. For this reason, As a result

c)

1. Linker: so ; Reason: Her sofa was getting old ; Result: she bought a new one.
2. Linker: Therefore, ; Reason: I hardly ever wore the jacket and I needed some money. ; Result: I sold it.
3. Linker: because ; Reason: they didn't accept cards. ; Result: We paid in cash