Although on your iBT TOEFL today there is no longer any direct grammar testing, it is still necessary to possess advanced grammar skills in order to score successfully on all the tasks in the test.
In speaking task in all of 6 sections you will be given the maximum of 1 minute time to speak up your mind on a given topic/situation. It is important that you not only use appropriate vocabulary and speak fluently, but also present your speech grammatically correct using complex and diverse sentence structures. According to the ETS requirements you are expected to "demonstrate effective use of grammar" and "exhibit a high degree of automaticity, with good control of basic and complex structures."
In writing section iBT TOEFL level 5 essay it is also necessary to use syntactically different correct sentences, appropriate vocabulary and idiomatic expressions. However, minor lexical or grammatical mistakes are permissible.
If you decided to prepare for the TOEFL exam on your own, you surely will need to find a good grammar book that will cover all the necessary material for the test. There is a great variety of such books today on the marketj; some of the best ones include grammar books by Murphy, Azar, Swan and others.
The scope of topics for your consideration comprises:
• verb tenses;
• all parts of speech
• modal verbs;
• parts of sentence;
• noun / adjective/ adverb clauses;
• prepositional phrases;
• parallel structures;
• word order and word choice;
• word forms;
Bare in mind that in speaking and writing sections it is your responsibility to choose the correct grammatical structure and active vocabulary to effectively convey your thoughts and ideas.