Since we're seeing a lot of pasta and restaurant statements I'll post my favorite Learn Italian site. http://ocw.mit.edu/courses/experimental-study-group/es-s41-speak-italian-with-your-mouth-full-spring-2012/ Italian lessons with recipes from MIT. And very enjoyable classes.
If you are new here have a look at these sites.
These are unofficial guidelines created by other learners to help us all. There are others on specific topic e.g. Immersion etc. At the bottom of this page you can look up the Official Duo Guidelines which are general but mandatory. My first piece of advice to anyone new is: "Always chose the first word given on hover." And don't be overconfident of that. For whatever you need to ask come to the comment/discuss section there will be someone to give advice. Most of what we learn comes from them. There are helpful sites offered which I bookmark and return to etc.
Of course the Moderators and Staff have the final word and they are unstinting in their time and assistance. Good luck. Enjoy.
Also a big part of language learning (arguably the biggest part of it) is to fail. and fail. and fail. Don't be embarrassed by it. Try not to get too frustrated by it. Embrace it. See it is an opportunity to learn and get better. Better for you to fail because the hover hint was wrong, then subsequently come here and have the word explained to you in detail than to get it right and forget the word entirely 20 seconds later.
Sometimes the alternative answers are incomplete and we should hit the flag button to say our answers should be accepted to help fill in the missing answers. We should be careful, though, that the context makes sense when using different homonyms, and also beware of similar-sounding words which are not actually the same (pasto means "meal", not pasta).
Alternative answers for each question are not necessarily complete as there can be numerous alternative answers for a single sentence. If you wrote "we leave the paste on the plate" exactly with no typos, then it would be worth hitting the flag button and selecting "my answer should be accepted". Of course the context makes "pasta" more likely, which is why "paste" may not have been added yet when you tried this question, since most users wouldn't think to try it.
Sometimes prepositions in English and Italian don't perfectly correspond.
"Nel piatto" means "on the plate". "Al piatto" means "to the plate" or "to the dish" as in this example from Reverso:
La foglia di banana dà un sapore speciale al piatto.
The grilled banana leaf gives a special flavour to the dish.