Verb conjugation of "controvert" in English

As I have already mentioned in my last email, it is a breakthrough, I have never been so successful. I have visited several Spanish schools and would like to discuss that by telephone with you.
The snow can be compared with white veil. Here in Davos, there is lots of new snow, so fresh and powdery snow, which is great for skiing. One needs to be careful from unexpected avalanches.
I can already speak a little English but not too well. So I'm more cautious about making mistakes. I want to improve my English, because it is also good for your confidence and communication skills.