Any web references for correct syntax use?

It’s unclear whether you want this in English or Italian, but I think what you’re looking for is a reference for idioms. If you google the word, you’ll find many out there. Here’s one that has lots of examples: The Idiom Connection .

Or maybe you’re looking for collocations.

Students will naturally transfer lexicon from L1 into L2 and one of the challenges of mastering a new language is to know the right equivalents to convey the meaning we need to express. Coming up with enough examples in class takes years of practice and repetition; i.e. teaching the same thing over and over. One way I do it too is by keeping a list of examples for verbs that you know are confusing, and also of cognates, collocations, verbs that have several meanings, idioms, verbal phrases, etc. For example, in English there are two verbs for the action of lending something and in Spanish, there is only one: Lend & borrow= prestar. Likewise, in Spanish there are two verbs ser & estar= to be in English. This list will be part of you supporting material in class so that you don’t have to have all these examples at the top of your head. I have been teaching languages for about 25 years and have come up to the conclusion that the best materials and examples that you can have are the ones that you prepare yourself and that you can customize to your teaching style and audience.

I’m thinking that what you really need is not a syntax site (syntax in English is extremely simple and most grammar sites will have the basic info [declarative, interrogative, imperative, exclamatory, simple, compund, complex]) but they won’t necessarily provide the examples of the verbs you actually need in your classes. For that purpose, I find dictionaries like this and this very useful because they provide both the meaning and the usage of words.

Depending on the level of my students I don’t like to overwhelm them with the many possible uses of a word and usually stick to the most used meanings and the usage that suits the context I’m dealing with. In time, they will look up uses for other situations on their own.

I love this question and am delighted to have learned something new this morning. Having been interested in language and languages all my adult life, I’ve thought about L1 and L2 intuitively, but never knew that the concept was codified

Following @morphail and @Porifera, you need a corpus.

I’ve actually found that the BNC Baby meets my classroom needs extremely well. £21 for a representative corpus (not much use to applied linguists, but a goldmine for teachers) seems like a pretty good deal to me.

Xaira is a powerful (but not exactly intuitive, last time I used it) concordancer which comes free with BNC Baby (although it’s FLOSS and you should never have to pay for it). If you need a simpler concordancer that is perhaps more appropriate for your learners, I suggest Antconc – it has a much simpler (though concomitantly less powerful, I guess) interface that does the basics well.