Yup, acetone should give only one singlet I think. All 6 H's are equivalent.Wouldn't acetone give 2 singlets as well? Or is it because there's symmetry, so only one H singlet is shown since they overlap? And 1,4 dimethoxybenzene shows two singlets because one from the aromatic H and one from the methoxy H? The other methoxy H and aromatic H's are equivalent so would just overlap, leading to only two visible singlets? Am I correct?