Encara no tenim significats per a "flat underside".
1Its flat underside helps orchestra members hear one another.
2It had a wide, flat underside, unbroken by windows or any opening except along the middle line.
3The completely flat underside improves aerodynamics.
4It had a flat underside, and a topside that still looked to him like the rounded top half of a loaf of baker's bread.
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