1. www.dictionary.com
A good resource to use when understanding words, and making sure you use the correct tense in your sentences.
Type a word in the search box
Click enter
You will be shown a page that looks like this (I typed in 'ran'):
The entire page will show you the correct ways to use the word in a sentence.
2. Thesaurus
adj = adjective
v = verb
pron = pronoun
v = verb
pron = pronoun
Happy Writing!