Research has shown that learning a known-and-unknown word combination leads to greater learning than learning an unknown word alone (Kasahara, 2010, 2011). These studies found that attaching a known adjective to an unknown noun can help learners remember the unknown noun. Kasahara (2015) found that a known verb can serve as an effective cue to remember an unknown noun in a known-and-unknown combination. To examine useful cues to learn unknown verbs, this study compared verb (unknown) + noun (known) combinations to verb (unknown) + adverb (known) combinations. Additionally, we explored how learners' vocabulary size would affect the known-and-unknown two-word combination learning to deepen our understanding of the characteristics of students who benefit from combination learning. The participants in each group learned 18 two-word combinations consisting of the same unknown target verbs and different known cues (nouns or adverbs). The participants were provided with a five-minute learning phase and two immediate recall tests: a Single Word Test, to write down the L1 meanings of the targets, and a Combination Test, to write down the L1 meanings of the combinations. The same two tests were administered one week later. The results showed that known nouns were better cues for learning unknown verbs than known adverbs. It was also found that participants with a larger vocabulary size benefited more from two-word combination learning.