Context: The verbal system lacks a distinctive future tense (the present tense serves here) and features special forms to express an action performed by an undetermined subject (the "impersonal").

Question: From what system is a distinctive future tense lacking?
Answer: verbal system

Question: What is used in place of the future tense?
Answer: present tense

Question: What does Estonian use to show actions performed by an undecided subject?
Answer: special forms

Question:  From what system is a distinctive future tense prominent?
Answer: Unanswerable

Question: What is used in place of the past tense?
Answer: Unanswerable

Question: What does Estonian use to show actions performed by an determined subject?
Answer: Unanswerable

Question: What is performed by the undetermined subject?
Answer: Unanswerable