This year I have students who have so many difficulties in English that when I tell them to write a composition in English, they tend to write it in Portuguese and only then translate it into English. They like using the “Google Translator” to perform this task.
Although the “Google Translator” can be a help, they cannot trust it entirely because the same word can have many different meanings depending on the context it is used. It is a fact that the “Google Translator” has been improving much, but you need to check your work before you deliver it to be evaluated.
In the web, I have found excellent sites where words/ expressions are used in different contexts, so it could be a great help when you are unsure about the best word to use.
Here are some examples:http://www.infopedia.pt/portugues-ingles/