"We have so much to offer."
Translation:Abbiamo tanto da offrire.
I'd like to know that as well. I've been relying on luck and memory of what I've seen before. I have a feeling we're just going to have to memorise a lot but maybe these links might help? http://answers.yahoo.com/question/index?qid=20130906004535AA9sS0r and http://lifmo.wordpress.com/2011/10/12/131/
The essence from the linked comment is as follows:
"per" is used when you want to express a purpose;
Io mangio poco per dimagrire ---> I eat little to lose weight
"da" is used to express that something is to be done;
Questo edificio è da ricostruire ---> This building is to be rebuilt
"a" is used to express an action that has just started;
Romeo ha cominciato a fumare ----> Romeo has started to smoke
"di" is used to express an action that has just stopped;
Romeo ha smesso di fumare ----> Romeo has given up smoking
well, it depends on how the infinitive is used. "Da offrire" is a final clause, and in Italian a way to express them is "da + infinitive". In the sentence "Non dimenticarti di pulire!" [don' t forget to clean up!], "di" introduces another type of expression, the "proposizione oggettiva" (http://it.wikipedia.org/wiki/Proposizione_oggettiva) in the indirect form. So, there are many ways to use infinitives in Italian, depending of the meaning that one wants to express and one has to memorise some Italian grammar to understand the right prepositions to use.
"così tanto" is a stronger form than "molto". Perhaps there could be other viable translations, like "abbiamo moltissimo da offire", depending on the rest of the text. If the sentence was "I loved you so much, but now it's over" I would translate it with "ti ho amato cosí tanto ma ora è finita", while "come to our showroom, we have so much to offer" can also be "vieni nel nostro showroom, abbiamo moltissimo da offrire".
"d'" would be "di" shortened for the following vowel.
here is a web page that may help: http://99problemi.com/pagine/Verbs_Prepositions.html#a and another: http://www.yearlyglot.com/verb-preposition-infinitive-patterns-in-italian/ and another: https://www.thoughtco.com/italian-verbs-and-prepositions-2011671