I would like to describe how the multi word verb should be used in several situation. Multi word verb may be used to describe more parts of the activities. Gairn and Redman (1992:33) state that we are using this term to describe the large number of English vocabulary consisting of two, or sometimes three parts:
A “base” Verb-Preposition e.g. look into (investigate), get over (recover from)
A “base” Verb and Adverbial Particle (Phrasal Verb) e.g. break down (collapse), call of (cancel).
A “base” Verb-Adverbial Particle-Preposition e.g. put up with (tolerate).
As what I wrote in the above example illustrate that there are Verb-Preposition combination that meaning is not clear from the individual parts; this probably explains why certain grammar book and course writers include semantically opaque preposition verbs in the treatment of phrasal verb. In our experience the distinction does not pose of significance the teaching problem, but if you wish to pursue the different the writer refer you to one of the grammar books listed in the bibliography. For the writer purpose, the writer will use the term “Phrasal Verb” when referring specially to verb-adverbial particle, and multi-word verb to include semantically opaque prepositional verbs as well.
In some cases phrasal verbs retain the meaning of their individual verb and particle e.g. sit down, while in others the meaning can not be deducted from an understanding of the constituent parts e.g. take in (deceive or cheat some body). It is this later category that creates most difficulty and contributes to the mystique which surrounds multi-word verb for many foreign learners. Also contributing to the mystique is the fact that many phrasal verbs have-multiple meaning e.g. pick up can mean lift, acquire, collect, etc. Grammatically, students need to know whether a transitive multi word verb is phrasal or preposition. This is because phrasal verbs are separable.
e.g. take off your hat take it off
take your hat off (but not take off it)
while the prepositional verb are not:
e.g. look after the children
look after them.
(but not ‘look the children after or look them after’)
Finally, there is question of style, some command phrasal verb are informal and have one-word equivalents which are preferred in more formal contexts (e.g. put off/ postpone; get long means manage). Students will need to be aware of restrictions of these kinds. (Linatul Ainisiyah)