Английский язык. Определите видо-временные формы предложений

Сочетание 4 групп (Simple, Continuous, Perfect, Perfect-Continuous) в 3-х временах (Past, Present, Future) образуют СИСТЕМУ из 12-ти видо-временных форм английского глагола в активном залоге. У Вас Present simple. Надеюсь, что я не ошибаюсь.

During the latent period, HIV carriers who harbour the virus without any sign of illness can unknowingly infect others. - harbour - Present Simple Active; can - Present Simple (Modal Verb), infect - Simple Infinitve. On average, the dormant virus seems to be triggered into action three to six years after first invading human cells. - seems - Present Simple Active, to be triggered - Simple Passive Infinitive. When switched on, viral replication may speed along, producing new viruses that destroy fresh lymphocytes. - may - Present Simple (Modal Verb), speed - Simple Active Infinitive, destroy - Present Simple Active. As viral replication spreads, the lymphocyte destruction virtually sabotages the entire immune system. - spreads - Present Simple Active, sabotages - Present Simple Active. In essence, HI Viruses do not kill people, they merely render the immune system defenceless against other infections, e.g. yeast invasions, toxoplasmosis, cytome-galovirus, massive herpes infections, special forms of pneumonia that kill in half of all AIDS patients. - do not kill - Present Simple Active (negative), render - Present Simple Active, kill - Present Simple Active.