Complex sentence: The wings have a single spar with flanges of aligned glass fibre (unidirectional rovings) with a glass-balsa sandwich web and the fuselage has GRP-balsa stiffening cross-members.
Split into simpler sentences: The wings have a single spar with flanges of aligned glass fibre (uni-directional rovings) and a glass-balsa sandwich web. The fuselage has GRP-balsa stiffening cross-members.