Grammar

More about Modal Verbs...http://www.perfect-english-grammar.com/modal-verbs.html

Some more practice about Tenses...http://www.ego4u.com/en/cram-up/grammar/
http://www.englisch-hilfen.de/en/exercises_list/zeitformen.htm

What about Relative pronouns and clauses...http://www.ego4u.com/en/cram-up/grammar/relative-clauses/exercises?02

If you want....
http://www.ego4u.com/en/cram-up/grammar/conditional-sentences

It´s done...
http://www.nonstopenglish.com/lang/es/allexercises/grammar/grammar-passive_voice.asp

Causative have....http://www.eoioviedo.org/anacarmen/passive/causative%20verbs.pdf

Somewhere, something.....http://www.shertonenglish.com/resources/es/pronouns/pronouns-indefinite.php