This study examines the extent of scope and the combination aspects of `-gess- (-겠-)` in a `-go(-고)` conjunctive sentence by comparing it with the prefinal endings `-eoss- (-었-)-` and `-si- (-시-)`. It is concluded that the scope of the pre-final ending `-eoss- (-었-)` is widest, followed by `-gess- (-겠-)` and `-si- (-시-)` in order; in particular, `-시-` has the narrowest scope. The scope of `-gess- (-겠-)` is not much affected by specific meanings, such as speculation, will, and future. However, the usage of `-gess- (-겠-)` with an implied nuance of politeness has a peculiar characteristic in terms of its scope and combination aspects, suggesting that this use of `-gess- (-겠-)` may be categorized differently than the `-gess- (-겠-)` used in the senses of presumption, intention, and future. On the other hand, in `-go(-고)` conjunctive sentences, the combination aspects of `-gess- (-겠-)` and `-eoss- (-었-)-` are related to the degree of independence between the preceding and succeeding clauses. Because the preceding and succeeding clauses are independent in a coordinate-conjoined sentence, the pre-final endings `-gess- (-겠-)` and `-eoss- (-었-)` can be combined respectively. However, in a subordinate-conjoined sentence, the combination of pre-final endings is restricted because the relationship between the preceding clause and the succeeding clause is dependent. Further, the pre-final ending `-si- (-시-)` can be combined with the preceding clause in all cases except simultaneous enumeration. This exception is related more to whether the movement of the preceding clause has continuance than to the independence of the preceding and succeeding clauses. In this way, the semantic relation of `-go(-고)` conjunctive sentences could be identified by examining the scope and combination aspects of pre-final endings.