This study investigates how tense feature affects CP’s Case-assignment. Chomsky (1980) proposed that tense is the feature which assigns Case to subject in tensed finite clauses. Chomsky (1980)’s argument, in turn, has justified the widely accepted view that untensed clauses do not assign Case. This study, however, attempts to show that, in reality, there exists a considerable amount of data that suggest that untensed clauses assign Case as well and this possibility was, initially, addressed, in depth, in Park (2020). This study argues that tense is not the sole factor which contributes to assignment of Case to subject and that Case-assignment to subject can be triggered by other factors such as marking of a sentence as a proposition in English. This study also reveals that Park (2020)’s attempt to analyze the derivation of relative clauses under the perspective of movement nicely converges with Case-assignment theory. In the meantime, this approach also provides a principled account of the phenomenon that anaphor-binding relation holds between a head noun(antecedent) and anaphor in relative clauses. Lastly, this study also reveals that subject case marker-dropping in untensed non-finite clauses in Korean is triggered by the syntactic environment in which the subject does not have agentive theta-role.