1 Antique furniture is expensive, but you can find it cheaply in England.
4 He had luggage with him which I helped him to carry. = plenty of / much
He had 'much luggage' sounds wrong- we generally use 'much' in the negative. However, 'plenty of' also sounds weird because it sounds positive. I'd say 'lots of', unless I aprticularlyenjoyed lugging someone's bags around.
5 I gave him excellent advice about looking after the canary but of course he didnt take .
= a) X / some b) IT
I'll be back later for more.