Transitivity system Thirdly,the tense in mental process is usually the simple present tense. Fourthly,the mental process is a two-way process, e.g.I fear it--It frightens me. I believe it--It convinces me. In mental process,one participant,which is a conscious being,that is feeling,thinking or seeing,is called "Senser".The other participant, which is "sensed"--felt,thought or seen,is called "Phenomenon"Thirdly, the tense in mental process is usually the simple present tense. Fourthly, the mental process is a two-way process, e.g. I fear it--It frightens me. I believe it--It convinces me. In mental process, one participant, which is a conscious being, that is feeling, thinking or seeing, is called "Senser". The other participant, which is "sensed"--felt, thought or seen, is called "Phenomenon". Transitivity system