Some da– compounds are used before a clause beginning with daß or a dependent infinitive construction with zu. These are anticipatory da– words:
Mein Vater hat nichts dagegen, daß wir oft ins Kino gehen.
My father has nothing against the fact that we go to the movies often.
[or:] My father has nothing against our going to the movies often.
Wir denken oft daran, nach Deutschland zu reisen.
We often think of travelling to Germany.
In both of these sentences, the da– compound serves the grammatical function of allowing the entire dependent clause to serve as the object of the preposition within the da– compound. In other words, in the first sentence, you are learning to recognize that the entire daß clause is the object of the preposition gegen. Likewise, in the second sentence, the dar– prefix serves like a signpost so that you will see the neighboring infinitive clause as the object of the preposition an. Observe how this same relationship gets expressed quite literally in the English translations.
Be sure to remember that the preposition captured inside of a da– compound still communicates its normal meaning within its local clause. In the first example above, note how the meaning of gegen is still crucial to understanding the first clause, as part of the idiomatic phrase nichts gegen etwas haben. In the second example, note how an is still functioning in its capacity of determining which meaning of denken is in use here (see dictionary for denken + an).
By the way, generally speaking, when the da-word refers to an idea in which the subject is different from the subject of the main clause, the da-word will point to a dependent clause (a complete statement with subject, verb, predicate). See the first example above. Whereas when the subjects are the same, an infinitive phrase with zu is used, as in the second example above.
More examples for you to work through on your own:
Morgen sprechen wir darüber, wie wir das bezahlen werden.
Tomorrow we’ll talk about how we’re going to pay for that.
Eine Vielzahl von Fehlern in medizinischen Doktorarbeiten ist auch darauf zurückzuführen, dass die Betreuungssituation nicht so gut ist.
A number of errors in medical dissertations can also be traced back to the fact that the advising situation is not so great.
Sie träumt davon, eine Pflanze zu werden.
She dreams of becoming a plant.