The generating series of the Gromov--Witten invariants naturally give rise to q-expansions as well as $\tau$-expansions. From the perspective of matching the Gromov--Witten theory with another enumerative theory--the FJRW theory, the $\tau$-expansions are more natural than the $q$-expansions. I will explain the LG/CY correspondence for the elliptic orbifold curves via modularity, and discuss some properties of the $\tau$-expansions of the corresponding quasi-modular forms from the perspective of the enumerative theories.