Das can only mean "this" as a pronoun. Use dies for the adjective "this" (whenever it's attached to something).

Dieses Bier ist stark.
This beer is strong.

Das ist ein stark Bier.
That is a strong beer.

Das Bier ist stark.
The beer is strong.

That would be "the beer is strong" instead of "this beer is strong"

I was wondering the same. Anyone?

You know how the word for "the" has to match the gender of the noun?

der Mann = "the man"
die Frau = "the woman"
das Auto = "the car"

Well, the word for "this [something]" has to match the gender too. You will notice that the endings are the same as for the forms of "the".

dieser Mann = "this man"
diese Frau = "this woman"
dieses Auto = "this car"

• One thing that is confusing at first is that there's a difference between "this [something]" and just "this" without a noun after it. If you don't have a noun after it you can use dies, regardless of the gender of what you're talking about. If you said the sentence Dies ist stark! you could be talking about anything.

• If you use the form of "this" with endings without a noun, e.g. Dieses ist stark! then it can only refer to something with the matching gender (here neuter). Translated, it means something like "this one". It has to be clear from context what you're talking about, otherwise (as in English) someone is likely to ask "this what?".

Schwer means 'heavy' or 'difficult'