linking words

Hello

Please I need help with these sentences:

1)'Our dinning room is a place which we keep strictly for eating as opposed to/whereas the sitting room, which is for sitting,talking and watching TV.'

* In this sentence my workbook says that the right answer is 'as opposed to', but I can't see the difference.

2)'the weather is likely to be dry and warm.In the far north-west of Scotland, however/whereas, it will be wet and windy.'

* In this one it says that 'however' is right but I don't understand why 'whereas' can't be right.

3)'By and large I'm very pleased with their work on our home. At any rate/having said that I think they could have made a better job of the painting'.

* In number 3 the correct answer is 'having said that'. Why not ' at any rate'.

thank you very much.
ANa

[aliaa]

1)'Our dinning room is a place which we keep strictly for eating as opposed to/whereas the sitting room, which is for sitting,talking and watching TV.'

** I think that if you choose whereas the sentence is incomplete, the other reason is that :whereas is used to contrast facts, but as opposed to is used to contrast things.

2)'the weather is likely to be dry and warm.In the far north-west of Scotland, however/whereas, it will be wet and windy.'

** however here means although


I hope I am correct, anyway we will see what tdol says about that