Hi Monichka,
The christmas pudding you mentioned is also called plum pudding.
I am reliably informed that it is not hard to make,but it takes quite a long time.I don't like it so i am not the best person to tell you about it.
I think it's much easier for people to just go to the shop and buy it.

I haven't seen either of those films you mentioned, are they romantic films?
I don't watch 'changing places' either,what's the name of the presenter in it that you fancy?

The phrase is 'by the bye' = incidentally or by the way.Don't use it as it is
an antiquated saying.Use 'by the way' or 'incidentally'.

'an' is used instead of 'a' infront of a vowel and sometimes before an initial 'h'
You would say "an honest man" which is correct not "a honest man" which is incorrect.
The rule is the letter 'a' should be used before all words beginning with a consonant except words that start with a silent 'h',[e.g, an honour,an hour ,an heir].Also use 'a' before a vowel if it sounds like it begins with the letter 'y',[e.g, a union, a use ,a eulogy, a university].
The best rule to remember is:
Use 'a' before a consenant sound,
Use 'an' before a vowel sound.
If you stick to this you can't go wrong.
Just to confuse you a little, there are some words which are weakly stressed and you can use either 'a' or 'an' with them.
Such as [,historic/historical/hotel]. 99% of people here would say
"I'm off to an hotel" or "it was an historic occasion",but you could say them both using 'a'.This is all due to development of the English language and words such as [historic,hotel] are in transition.
In the King james version of the bible you may see words such as [an hundred] now we see the same historical change .
As we are in this period of historical change, with words which it depends on how you pronounce them,as they can be pronounced both ways[e.g,herb,humble,hotel],use 'a' or 'an' according to your own personal pronunciation preferences.

If you are unsure of anything let me know,
See you later,mate.