If you are English students and you want to improve your vocabulary/comprehension skills I suggest that you try this website. Lingro is an amazing resource if you want to read a blog, an online newspaper, etc. You just have to write the link of what you want to read (number one in the picture below). You can select a dictionary (as you can see, I marked “English dictionary” with a red rectangle, but it’s not the only one, there are also English-Spanish, Spanish-English, English-French, English-Italian, etc.).
This is the homepage:

Link: http://lingro.com/

For example, you want to read an article on the website http://www.nationalgeographic.com/ . Firstly, you have to find an article you like, for instance, I decided to read this one: http://news.nationalgeographic.com/2015/04/150406-california-drought-snowpack-map-water-science/

Then, you have to copy the article’s link. Done that, from within the lingro’s website, you can enter the URL.
It’ll appear like this:

You can notice that I selected (I clicked the left mouse button) “warming” and “scarcity” .
Afterwards, you can study the words you didn’t know. There’s the possibility to create wordlists:

You can also play with flashcards: