  Moir\'e superlattices (MSL) formed in angle-aligned bilayers of van der Waals
materials have become a promising platform to realize novel two-dimensional
electronic states. Angle-aligned trilayer structures can form two sets of MSLs
which could potentially interfere with each other. In this work, we directly
image the moir\'e patterns in both monolayer graphene aligned on hBN and
twisted bilayer graphene aligned on hBN, using combined scanning microwave
impedance microscopy and conductive atomic force microscopy. Correlation of the
two techniques reveals the contrast mechanism for the achieved ultrahigh
spatial resolution (<2 nm). We observe two sets of MSLs with different
periodicities in the trilayer stack. The smaller MSL breaks the 6-fold
rotational symmetry and exhibits abrupt discontinuities at the boundaries of
the larger MSL. Using a rigid atomic-stacking model, we demonstrate that the
hBN layer considerably modifies the MSL of twisted bilayer graphene. We further
analyze its effect on the reciprocal space spectrum of the dual-moir\'e system.
