It may be necessary to stop__in the learning process and go back to the difficult points in the lessons. A. at intervals B. at random C. at ease D. at length 答案:C下列对脂质的表述中,不正确的是( )A.主要由碳、氢、氧元素构成的的生物分子B.具有极性因此都溶于水C.构成细胞膜的主要成分的磷脂就是脂质的一种D.脂肪、性激素和VD都属于脂质