Nominalization is the most typical structure of IGM, particularly in scientific, political discourse etc. Halliday and Matthiessen (2004) point out that information density, nominalization and GM are as the foremost lexico-grammatical features of the academic and written language. They also state that nominalization has been recognized as the sole most substantial resource for establishing GMs. In short, the major reflection of the IGM is nominalization, for instance, trains head-on collision is a metaphorical variant of trains collided head-on in which the process collide is rendered in a nominal type of construction. In the English transitivity system, there are six main types of process: material, relational, mental, verbal, behavioral and existential processes.