In various embodiments, the present teachings provide sequencing methods which facilitate enhancing the efficiency of ligation and/or increasing sequencing reads. Various embodiments of the methods enable sequencing through template regions for which complementary labeled extension probes are unavailable or insufficient. In various embodiments, one or more rounds of ligation with unlabeled extension probes can be used in addition to a round of ligation with labeled extension probe. In various embodiments, for example, such methods can facilitate extension on template polynucleotides that do not bind labeled extension probe in the first round of ligation.